content.js

(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
(function (global){
/**
 * @license
 * lodash 3.9.3 (Custom Build) <https://lodash.com/>
 * Build: `lodash modern -d -o ./index.js`
 * Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */
;(function() {

  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
  var undefined;

  /** Used as the semantic version number. */
  var VERSION = '3.9.3';

  /** Used to compose bitmasks for wrapper metadata. */
  var BIND_FLAG = 1,
      BIND_KEY_FLAG = 2,
      CURRY_BOUND_FLAG = 4,
      CURRY_FLAG = 8,
      CURRY_RIGHT_FLAG = 16,
      PARTIAL_FLAG = 32,
      PARTIAL_RIGHT_FLAG = 64,
      ARY_FLAG = 128,
      REARG_FLAG = 256;

  /** Used as default options for `_.trunc`. */
  var DEFAULT_TRUNC_LENGTH = 30,
      DEFAULT_TRUNC_OMISSION = '...';

  /** Used to detect when a function becomes hot. */
  var HOT_COUNT = 150,
      HOT_SPAN = 16;

  /** Used to indicate the type of lazy iteratees. */
  var LAZY_DROP_WHILE_FLAG = 0,
      LAZY_FILTER_FLAG = 1,
      LAZY_MAP_FLAG = 2;

  /** Used as the `TypeError` message for "Functions" methods. */
  var FUNC_ERROR_TEXT = 'Expected a function';

  /** Used as the internal argument placeholder. */
  var PLACEHOLDER = '__lodash_placeholder__';

  /** `Object#toString` result references. */
  var argsTag = '[object Arguments]',
      arrayTag = '[object Array]',
      boolTag = '[object Boolean]',
      dateTag = '[object Date]',
      errorTag = '[object Error]',
      funcTag = '[object Function]',
      mapTag = '[object Map]',
      numberTag = '[object Number]',
      objectTag = '[object Object]',
      regexpTag = '[object RegExp]',
      setTag = '[object Set]',
      stringTag = '[object String]',
      weakMapTag = '[object WeakMap]';

  var arrayBufferTag = '[object ArrayBuffer]',
      float32Tag = '[object Float32Array]',
      float64Tag = '[object Float64Array]',
      int8Tag = '[object Int8Array]',
      int16Tag = '[object Int16Array]',
      int32Tag = '[object Int32Array]',
      uint8Tag = '[object Uint8Array]',
      uint8ClampedTag = '[object Uint8ClampedArray]',
      uint16Tag = '[object Uint16Array]',
      uint32Tag = '[object Uint32Array]';

  /** Used to match empty string literals in compiled template source. */
  var reEmptyStringLeading = /\b__p \+= '';/g,
      reEmptyStringMiddle = /\b(__p \+=) '' \+/g,
      reEmptyStringTrailing = /(__e\(.*?\)|\b__t\)) \+\n'';/g;

  /** Used to match HTML entities and HTML characters. */
  var reEscapedHtml = /&(?:amp|lt|gt|quot|#39|#96);/g,
      reUnescapedHtml = /[&<>"'`]/g,
      reHasEscapedHtml = RegExp(reEscapedHtml.source),
      reHasUnescapedHtml = RegExp(reUnescapedHtml.source);

  /** Used to match template delimiters. */
  var reEscape = /<%-([\s\S]+?)%>/g,
      reEvaluate = /<%([\s\S]+?)%>/g,
      reInterpolate = /<%=([\s\S]+?)%>/g;

  /** Used to match property names within property paths. */
  var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\n\\]|\\.)*?\1)\]/,
      reIsPlainProp = /^\w*$/,
      rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\n\\]|\\.)*?)\2)\]/g;

  /**
   * Used to match `RegExp` [special characters](http://www.regular-expressions.info/characters.html#special).
   * In addition to special characters the forward slash is escaped to allow for
   * easier `eval` use and `Function` compilation.
   */
  var reRegExpChars = /[.*+?^${}()|[\]\/\\]/g,
      reHasRegExpChars = RegExp(reRegExpChars.source);

  /** Used to match [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks). */
  var reComboMark = /[\u0300-\u036f\ufe20-\ufe23]/g;

  /** Used to match backslashes in property paths. */
  var reEscapeChar = /\\(\\)?/g;

  /** Used to match [ES template delimiters](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-template-literal-lexical-components). */
  var reEsTemplate = /\$\{([^\\}]*(?:\\.[^\\}]*)*)\}/g;

  /** Used to match `RegExp` flags from their coerced string values. */
  var reFlags = /\w*$/;

  /** Used to detect hexadecimal string values. */
  var reHasHexPrefix = /^0[xX]/;

  /** Used to detect host constructors (Safari > 5). */
  var reIsHostCtor = /^\[object .+?Constructor\]$/;

  /** Used to detect unsigned integer values. */
  var reIsUint = /^\d+$/;

  /** Used to match latin-1 supplementary letters (excluding mathematical operators). */
  var reLatin1 = /[\xc0-\xd6\xd8-\xde\xdf-\xf6\xf8-\xff]/g;

  /** Used to ensure capturing order of template delimiters. */
  var reNoMatch = /($^)/;

  /** Used to match unescaped characters in compiled string literals. */
  var reUnescapedString = /['\n\r\u2028\u2029\\]/g;

  /** Used to match words to create compound words. */
  var reWords = (function() {
    var upper = '[A-Z\\xc0-\\xd6\\xd8-\\xde]',
        lower = '[a-z\\xdf-\\xf6\\xf8-\\xff]+';

    return RegExp(upper + '+(?=' + upper + lower + ')|' + upper + '?' + lower + '|' + upper + '+|[0-9]+', 'g');
  }());

  /** Used to detect and test for whitespace. */
  var whitespace = (
    // Basic whitespace characters.
    ' \t\x0b\f\xa0\ufeff' +

    // Line terminators.
    '\n\r\u2028\u2029' +

    // Unicode category "Zs" space separators.
    '\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000'
  );

  /** Used to assign default `context` object properties. */
  var contextProps = [
    'Array', 'ArrayBuffer', 'Date', 'Error', 'Float32Array', 'Float64Array',
    'Function', 'Int8Array', 'Int16Array', 'Int32Array', 'Math', 'Number',
    'Object', 'RegExp', 'Set', 'String', '_', 'clearTimeout', 'document',
    'isFinite', 'parseFloat', 'parseInt', 'setTimeout', 'TypeError', 'Uint8Array',
    'Uint8ClampedArray', 'Uint16Array', 'Uint32Array', 'WeakMap', 'window'
  ];

  /** Used to make template sourceURLs easier to identify. */
  var templateCounter = -1;

  /** Used to identify `toStringTag` values of typed arrays. */
  var typedArrayTags = {};
  typedArrayTags[float32Tag] = typedArrayTags[float64Tag] =
  typedArrayTags[int8Tag] = typedArrayTags[int16Tag] =
  typedArrayTags[int32Tag] = typedArrayTags[uint8Tag] =
  typedArrayTags[uint8ClampedTag] = typedArrayTags[uint16Tag] =
  typedArrayTags[uint32Tag] = true;
  typedArrayTags[argsTag] = typedArrayTags[arrayTag] =
  typedArrayTags[arrayBufferTag] = typedArrayTags[boolTag] =
  typedArrayTags[dateTag] = typedArrayTags[errorTag] =
  typedArrayTags[funcTag] = typedArrayTags[mapTag] =
  typedArrayTags[numberTag] = typedArrayTags[objectTag] =
  typedArrayTags[regexpTag] = typedArrayTags[setTag] =
  typedArrayTags[stringTag] = typedArrayTags[weakMapTag] = false;

  /** Used to identify `toStringTag` values supported by `_.clone`. */
  var cloneableTags = {};
  cloneableTags[argsTag] = cloneableTags[arrayTag] =
  cloneableTags[arrayBufferTag] = cloneableTags[boolTag] =
  cloneableTags[dateTag] = cloneableTags[float32Tag] =
  cloneableTags[float64Tag] = cloneableTags[int8Tag] =
  cloneableTags[int16Tag] = cloneableTags[int32Tag] =
  cloneableTags[numberTag] = cloneableTags[objectTag] =
  cloneableTags[regexpTag] = cloneableTags[stringTag] =
  cloneableTags[uint8Tag] = cloneableTags[uint8ClampedTag] =
  cloneableTags[uint16Tag] = cloneableTags[uint32Tag] = true;
  cloneableTags[errorTag] = cloneableTags[funcTag] =
  cloneableTags[mapTag] = cloneableTags[setTag] =
  cloneableTags[weakMapTag] = false;

  /** Used as an internal `_.debounce` options object by `_.throttle`. */
  var debounceOptions = {
    'leading': false,
    'maxWait': 0,
    'trailing': false
  };

  /** Used to map latin-1 supplementary letters to basic latin letters. */
  var deburredLetters = {
    '\xc0': 'A',  '\xc1': 'A', '\xc2': 'A', '\xc3': 'A', '\xc4': 'A', '\xc5': 'A',
    '\xe0': 'a',  '\xe1': 'a', '\xe2': 'a', '\xe3': 'a', '\xe4': 'a', '\xe5': 'a',
    '\xc7': 'C',  '\xe7': 'c',
    '\xd0': 'D',  '\xf0': 'd',
    '\xc8': 'E',  '\xc9': 'E', '\xca': 'E', '\xcb': 'E',
    '\xe8': 'e',  '\xe9': 'e', '\xea': 'e', '\xeb': 'e',
    '\xcC': 'I',  '\xcd': 'I', '\xce': 'I', '\xcf': 'I',
    '\xeC': 'i',  '\xed': 'i', '\xee': 'i', '\xef': 'i',
    '\xd1': 'N',  '\xf1': 'n',
    '\xd2': 'O',  '\xd3': 'O', '\xd4': 'O', '\xd5': 'O', '\xd6': 'O', '\xd8': 'O',
    '\xf2': 'o',  '\xf3': 'o', '\xf4': 'o', '\xf5': 'o', '\xf6': 'o', '\xf8': 'o',
    '\xd9': 'U',  '\xda': 'U', '\xdb': 'U', '\xdc': 'U',
    '\xf9': 'u',  '\xfa': 'u', '\xfb': 'u', '\xfc': 'u',
    '\xdd': 'Y',  '\xfd': 'y', '\xff': 'y',
    '\xc6': 'Ae', '\xe6': 'ae',
    '\xde': 'Th', '\xfe': 'th',
    '\xdf': 'ss'
  };

  /** Used to map characters to HTML entities. */
  var htmlEscapes = {
    '&': '&amp;',
    '<': '&lt;',
    '>': '&gt;',
    '"': '&quot;',
    "'": '&#39;',
    '`': '&#96;'
  };

  /** Used to map HTML entities to characters. */
  var htmlUnescapes = {
    '&amp;': '&',
    '&lt;': '<',
    '&gt;': '>',
    '&quot;': '"',
    '&#39;': "'",
    '&#96;': '`'
  };

  /** Used to determine if values are of the language type `Object`. */
  var objectTypes = {
    'function': true,
    'object': true
  };

  /** Used to escape characters for inclusion in compiled string literals. */
  var stringEscapes = {
    '\\': '\\',
    "'": "'",
    '\n': 'n',
    '\r': 'r',
    '\u2028': 'u2028',
    '\u2029': 'u2029'
  };

  /** Detect free variable `exports`. */
  var freeExports = objectTypes[typeof exports] && exports && !exports.nodeType && exports;

  /** Detect free variable `module`. */
  var freeModule = objectTypes[typeof module] && module && !module.nodeType && module;

  /** Detect free variable `global` from Node.js. */
  var freeGlobal = freeExports && freeModule && typeof global == 'object' && global && global.Object && global;

  /** Detect free variable `self`. */
  var freeSelf = objectTypes[typeof self] && self && self.Object && self;

  /** Detect free variable `window`. */
  var freeWindow = objectTypes[typeof window] && window && window.Object && window;

  /** Detect the popular CommonJS extension `module.exports`. */
  var moduleExports = freeModule && freeModule.exports === freeExports && freeExports;

  /**
   * Used as a reference to the global object.
   *
   * The `this` value is used if it's the global object to avoid Greasemonkey's
   * restricted `window` object, otherwise the `window` object is used.
   */
  var root = freeGlobal || ((freeWindow !== (this && this.window)) && freeWindow) || freeSelf || this;

  /*--------------------------------------------------------------------------*/

  /**
   * The base implementation of `compareAscending` which compares values and
   * sorts them in ascending order without guaranteeing a stable sort.
   *
   * @private
   * @param {*} value The value to compare.
   * @param {*} other The other value to compare.
   * @returns {number} Returns the sort order indicator for `value`.
   */
  function baseCompareAscending(value, other) {
    if (value !== other) {
      var valIsNull = value === null,
          valIsUndef = value === undefined,
          valIsReflexive = value === value;

      var othIsNull = other === null,
          othIsUndef = other === undefined,
          othIsReflexive = other === other;

      if ((value > other && !othIsNull) || !valIsReflexive ||
          (valIsNull && !othIsUndef && othIsReflexive) ||
          (valIsUndef && othIsReflexive)) {
        return 1;
      }
      if ((value < other && !valIsNull) || !othIsReflexive ||
          (othIsNull && !valIsUndef && valIsReflexive) ||
          (othIsUndef && valIsReflexive)) {
        return -1;
      }
    }
    return 0;
  }

  /**
   * The base implementation of `_.findIndex` and `_.findLastIndex` without
   * support for callback shorthands and `this` binding.
   *
   * @private
   * @param {Array} array The array to search.
   * @param {Function} predicate The function invoked per iteration.
   * @param {boolean} [fromRight] Specify iterating from right to left.
   * @returns {number} Returns the index of the matched value, else `-1`.
   */
  function baseFindIndex(array, predicate, fromRight) {
    var length = array.length,
        index = fromRight ? length : -1;

    while ((fromRight ? index-- : ++index < length)) {
      if (predicate(array[index], index, array)) {
        return index;
      }
    }
    return -1;
  }

  /**
   * The base implementation of `_.indexOf` without support for binary searches.
   *
   * @private
   * @param {Array} array The array to search.
   * @param {*} value The value to search for.
   * @param {number} fromIndex The index to search from.
   * @returns {number} Returns the index of the matched value, else `-1`.
   */
  function baseIndexOf(array, value, fromIndex) {
    if (value !== value) {
      return indexOfNaN(array, fromIndex);
    }
    var index = fromIndex - 1,
        length = array.length;

    while (++index < length) {
      if (array[index] === value) {
        return index;
      }
    }
    return -1;
  }

  /**
   * The base implementation of `_.isFunction` without support for environments
   * with incorrect `typeof` results.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
   */
  function baseIsFunction(value) {
    // Avoid a Chakra JIT bug in compatibility modes of IE 11.
    // See https://github.com/jashkenas/underscore/issues/1621 for more details.
    return typeof value == 'function' || false;
  }

  /**
   * Converts `value` to a string if it's not one. An empty string is returned
   * for `null` or `undefined` values.
   *
   * @private
   * @param {*} value The value to process.
   * @returns {string} Returns the string.
   */
  function baseToString(value) {
    if (typeof value == 'string') {
      return value;
    }
    return value == null ? '' : (value + '');
  }

  /**
   * Used by `_.trim` and `_.trimLeft` to get the index of the first character
   * of `string` that is not found in `chars`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @param {string} chars The characters to find.
   * @returns {number} Returns the index of the first character not found in `chars`.
   */
  function charsLeftIndex(string, chars) {
    var index = -1,
        length = string.length;

    while (++index < length && chars.indexOf(string.charAt(index)) > -1) {}
    return index;
  }

  /**
   * Used by `_.trim` and `_.trimRight` to get the index of the last character
   * of `string` that is not found in `chars`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @param {string} chars The characters to find.
   * @returns {number} Returns the index of the last character not found in `chars`.
   */
  function charsRightIndex(string, chars) {
    var index = string.length;

    while (index-- && chars.indexOf(string.charAt(index)) > -1) {}
    return index;
  }

  /**
   * Used by `_.sortBy` to compare transformed elements of a collection and stable
   * sort them in ascending order.
   *
   * @private
   * @param {Object} object The object to compare to `other`.
   * @param {Object} other The object to compare to `object`.
   * @returns {number} Returns the sort order indicator for `object`.
   */
  function compareAscending(object, other) {
    return baseCompareAscending(object.criteria, other.criteria) || (object.index - other.index);
  }

  /**
   * Used by `_.sortByOrder` to compare multiple properties of each element
   * in a collection and stable sort them in the following order:
   *
   * If `orders` is unspecified, sort in ascending order for all properties.
   * Otherwise, for each property, sort in ascending order if its corresponding value in
   * orders is true, and descending order if false.
   *
   * @private
   * @param {Object} object The object to compare to `other`.
   * @param {Object} other The object to compare to `object`.
   * @param {boolean[]} orders The order to sort by for each property.
   * @returns {number} Returns the sort order indicator for `object`.
   */
  function compareMultiple(object, other, orders) {
    var index = -1,
        objCriteria = object.criteria,
        othCriteria = other.criteria,
        length = objCriteria.length,
        ordersLength = orders.length;

    while (++index < length) {
      var result = baseCompareAscending(objCriteria[index], othCriteria[index]);
      if (result) {
        if (index >= ordersLength) {
          return result;
        }
        return result * (orders[index] ? 1 : -1);
      }
    }
    // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications
    // that causes it, under certain circumstances, to provide the same value for
    // `object` and `other`. See https://github.com/jashkenas/underscore/pull/1247
    // for more details.
    //
    // This also ensures a stable sort in V8 and other engines.
    // See https://code.google.com/p/v8/issues/detail?id=90 for more details.
    return object.index - other.index;
  }

  /**
   * Used by `_.deburr` to convert latin-1 supplementary letters to basic latin letters.
   *
   * @private
   * @param {string} letter The matched letter to deburr.
   * @returns {string} Returns the deburred letter.
   */
  function deburrLetter(letter) {
    return deburredLetters[letter];
  }

  /**
   * Used by `_.escape` to convert characters to HTML entities.
   *
   * @private
   * @param {string} chr The matched character to escape.
   * @returns {string} Returns the escaped character.
   */
  function escapeHtmlChar(chr) {
    return htmlEscapes[chr];
  }

  /**
   * Used by `_.template` to escape characters for inclusion in compiled
   * string literals.
   *
   * @private
   * @param {string} chr The matched character to escape.
   * @returns {string} Returns the escaped character.
   */
  function escapeStringChar(chr) {
    return '\\' + stringEscapes[chr];
  }

  /**
   * Gets the index at which the first occurrence of `NaN` is found in `array`.
   *
   * @private
   * @param {Array} array The array to search.
   * @param {number} fromIndex The index to search from.
   * @param {boolean} [fromRight] Specify iterating from right to left.
   * @returns {number} Returns the index of the matched `NaN`, else `-1`.
   */
  function indexOfNaN(array, fromIndex, fromRight) {
    var length = array.length,
        index = fromIndex + (fromRight ? 0 : -1);

    while ((fromRight ? index-- : ++index < length)) {
      var other = array[index];
      if (other !== other) {
        return index;
      }
    }
    return -1;
  }

  /**
   * Checks if `value` is object-like.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
   */
  function isObjectLike(value) {
    return !!value && typeof value == 'object';
  }

  /**
   * Used by `trimmedLeftIndex` and `trimmedRightIndex` to determine if a
   * character code is whitespace.
   *
   * @private
   * @param {number} charCode The character code to inspect.
   * @returns {boolean} Returns `true` if `charCode` is whitespace, else `false`.
   */
  function isSpace(charCode) {
    return ((charCode <= 160 && (charCode >= 9 && charCode <= 13) || charCode == 32 || charCode == 160) || charCode == 5760 || charCode == 6158 ||
      (charCode >= 8192 && (charCode <= 8202 || charCode == 8232 || charCode == 8233 || charCode == 8239 || charCode == 8287 || charCode == 12288 || charCode == 65279)));
  }

  /**
   * Replaces all `placeholder` elements in `array` with an internal placeholder
   * and returns an array of their indexes.
   *
   * @private
   * @param {Array} array The array to modify.
   * @param {*} placeholder The placeholder to replace.
   * @returns {Array} Returns the new array of placeholder indexes.
   */
  function replaceHolders(array, placeholder) {
    var index = -1,
        length = array.length,
        resIndex = -1,
        result = [];

    while (++index < length) {
      if (array[index] === placeholder) {
        array[index] = PLACEHOLDER;
        result[++resIndex] = index;
      }
    }
    return result;
  }

  /**
   * An implementation of `_.uniq` optimized for sorted arrays without support
   * for callback shorthands and `this` binding.
   *
   * @private
   * @param {Array} array The array to inspect.
   * @param {Function} [iteratee] The function invoked per iteration.
   * @returns {Array} Returns the new duplicate-value-free array.
   */
  function sortedUniq(array, iteratee) {
    var seen,
        index = -1,
        length = array.length,
        resIndex = -1,
        result = [];

    while (++index < length) {
      var value = array[index],
          computed = iteratee ? iteratee(value, index, array) : value;

      if (!index || seen !== computed) {
        seen = computed;
        result[++resIndex] = value;
      }
    }
    return result;
  }

  /**
   * Used by `_.trim` and `_.trimLeft` to get the index of the first non-whitespace
   * character of `string`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @returns {number} Returns the index of the first non-whitespace character.
   */
  function trimmedLeftIndex(string) {
    var index = -1,
        length = string.length;

    while (++index < length && isSpace(string.charCodeAt(index))) {}
    return index;
  }

  /**
   * Used by `_.trim` and `_.trimRight` to get the index of the last non-whitespace
   * character of `string`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @returns {number} Returns the index of the last non-whitespace character.
   */
  function trimmedRightIndex(string) {
    var index = string.length;

    while (index-- && isSpace(string.charCodeAt(index))) {}
    return index;
  }

  /**
   * Used by `_.unescape` to convert HTML entities to characters.
   *
   * @private
   * @param {string} chr The matched character to unescape.
   * @returns {string} Returns the unescaped character.
   */
  function unescapeHtmlChar(chr) {
    return htmlUnescapes[chr];
  }

  /*--------------------------------------------------------------------------*/

  /**
   * Create a new pristine `lodash` function using the given `context` object.
   *
   * @static
   * @memberOf _
   * @category Utility
   * @param {Object} [context=root] The context object.
   * @returns {Function} Returns a new `lodash` function.
   * @example
   *
   * _.mixin({ 'foo': _.constant('foo') });
   *
   * var lodash = _.runInContext();
   * lodash.mixin({ 'bar': lodash.constant('bar') });
   *
   * _.isFunction(_.foo);
   * // => true
   * _.isFunction(_.bar);
   * // => false
   *
   * lodash.isFunction(lodash.foo);
   * // => false
   * lodash.isFunction(lodash.bar);
   * // => true
   *
   * // using `context` to mock `Date#getTime` use in `_.now`
   * var mock = _.runInContext({
   *   'Date': function() {
   *     return { 'getTime': getTimeMock };
   *   }
   * });
   *
   * // or creating a suped-up `defer` in Node.js
   * var defer = _.runInContext({ 'setTimeout': setImmediate }).defer;
   */
  function runInContext(context) {
    // Avoid issues with some ES3 environments that attempt to use values, named
    // after built-in constructors like `Object`, for the creation of literals.
    // ES5 clears this up by stating that literals must use built-in constructors.
    // See https://es5.github.io/#x11.1.5 for more details.
    context = context ? _.defaults(root.Object(), context, _.pick(root, contextProps)) : root;

    /** Native constructor references. */
    var Array = context.Array,
        Date = context.Date,
        Error = context.Error,
        Function = context.Function,
        Math = context.Math,
        Number = context.Number,
        Object = context.Object,
        RegExp = context.RegExp,
        String = context.String,
        TypeError = context.TypeError;

    /** Used for native method references. */
    var arrayProto = Array.prototype,
        objectProto = Object.prototype,
        stringProto = String.prototype;

    /** Used to detect DOM support. */
    var document = (document = context.window) ? document.document : null;

    /** Used to resolve the decompiled source of functions. */
    var fnToString = Function.prototype.toString;

    /** Used to check objects for own properties. */
    var hasOwnProperty = objectProto.hasOwnProperty;

    /** Used to generate unique IDs. */
    var idCounter = 0;

    /**
     * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
     * of values.
     */
    var objToString = objectProto.toString;

    /** Used to restore the original `_` reference in `_.noConflict`. */
    var oldDash = context._;

    /** Used to detect if a method is native. */
    var reIsNative = RegExp('^' +
      escapeRegExp(fnToString.call(hasOwnProperty))
      .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
    );

    /** Native method references. */
    var ArrayBuffer = getNative(context, 'ArrayBuffer'),
        bufferSlice = getNative(ArrayBuffer && new ArrayBuffer(0), 'slice'),
        ceil = Math.ceil,
        clearTimeout = context.clearTimeout,
        floor = Math.floor,
        getPrototypeOf = getNative(Object, 'getPrototypeOf'),
        parseFloat = context.parseFloat,
        push = arrayProto.push,
        Set = getNative(context, 'Set'),
        setTimeout = context.setTimeout,
        splice = arrayProto.splice,
        Uint8Array = getNative(context, 'Uint8Array'),
        WeakMap = getNative(context, 'WeakMap');

    /** Used to clone array buffers. */
    var Float64Array = (function() {
      // Safari 5 errors when using an array buffer to initialize a typed array
      // where the array buffer's `byteLength` is not a multiple of the typed
      // array's `BYTES_PER_ELEMENT`.
      try {
        var func = getNative(context, 'Float64Array'),
            result = new func(new ArrayBuffer(10), 0, 1) && func;
      } catch(e) {}
      return result || null;
    }());

    /* Native method references for those with the same name as other `lodash` methods. */
    var nativeCreate = getNative(Object, 'create'),
        nativeIsArray = getNative(Array, 'isArray'),
        nativeIsFinite = context.isFinite,
        nativeKeys = getNative(Object, 'keys'),
        nativeMax = Math.max,
        nativeMin = Math.min,
        nativeNow = getNative(Date, 'now'),
        nativeNumIsFinite = getNative(Number, 'isFinite'),
        nativeParseInt = context.parseInt,
        nativeRandom = Math.random;

    /** Used as references for `-Infinity` and `Infinity`. */
    var NEGATIVE_INFINITY = Number.NEGATIVE_INFINITY,
        POSITIVE_INFINITY = Number.POSITIVE_INFINITY;

    /** Used as references for the maximum length and index of an array. */
    var MAX_ARRAY_LENGTH = 4294967295,
        MAX_ARRAY_INDEX = MAX_ARRAY_LENGTH - 1,
        HALF_MAX_ARRAY_LENGTH = MAX_ARRAY_LENGTH >>> 1;

    /** Used as the size, in bytes, of each `Float64Array` element. */
    var FLOAT64_BYTES_PER_ELEMENT = Float64Array ? Float64Array.BYTES_PER_ELEMENT : 0;

    /**
     * Used as the [maximum length](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.max_safe_integer)
     * of an array-like value.
     */
    var MAX_SAFE_INTEGER = 9007199254740991;

    /** Used to store function metadata. */
    var metaMap = WeakMap && new WeakMap;

    /** Used to lookup unminified function names. */
    var realNames = {};

    /*------------------------------------------------------------------------*/

    /**
     * Creates a `lodash` object which wraps `value` to enable implicit chaining.
     * Methods that operate on and return arrays, collections, and functions can
     * be chained together. Methods that return a boolean or single value will
     * automatically end the chain returning the unwrapped value. Explicit chaining
     * may be enabled using `_.chain`. The execution of chained methods is lazy,
     * that is, execution is deferred until `_#value` is implicitly or explicitly
     * called.
     *
     * Lazy evaluation allows several methods to support shortcut fusion. Shortcut
     * fusion is an optimization that merges iteratees to avoid creating intermediate
     * arrays and reduce the number of iteratee executions.
     *
     * Chaining is supported in custom builds as long as the `_#value` method is
     * directly or indirectly included in the build.
     *
     * In addition to lodash methods, wrappers have `Array` and `String` methods.
     *
     * The wrapper `Array` methods are:
     * `concat`, `join`, `pop`, `push`, `reverse`, `shift`, `slice`, `sort`,
     * `splice`, and `unshift`
     *
     * The wrapper `String` methods are:
     * `replace` and `split`
     *
     * The wrapper methods that support shortcut fusion are:
     * `compact`, `drop`, `dropRight`, `dropRightWhile`, `dropWhile`, `filter`,
     * `first`, `initial`, `last`, `map`, `pluck`, `reject`, `rest`, `reverse`,
     * `slice`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, `toArray`,
     * and `where`
     *
     * The chainable wrapper methods are:
     * `after`, `ary`, `assign`, `at`, `before`, `bind`, `bindAll`, `bindKey`,
     * `callback`, `chain`, `chunk`, `commit`, `compact`, `concat`, `constant`,
     * `countBy`, `create`, `curry`, `debounce`, `defaults`, `defer`, `delay`,
     * `difference`, `drop`, `dropRight`, `dropRightWhile`, `dropWhile`, `fill`,
     * `filter`, `flatten`, `flattenDeep`, `flow`, `flowRight`, `forEach`,
     * `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`, `functions`,
     * `groupBy`, `indexBy`, `initial`, `intersection`, `invert`, `invoke`, `keys`,
     * `keysIn`, `map`, `mapKeys`, `mapValues`, `matches`, `matchesProperty`,
     * `memoize`, `merge`, `method`, `methodOf`, `mixin`, `negate`, `omit`, `once`,
     * `pairs`, `partial`, `partialRight`, `partition`, `pick`, `plant`, `pluck`,
     * `property`, `propertyOf`, `pull`, `pullAt`, `push`, `range`, `rearg`,
     * `reject`, `remove`, `rest`, `restParam`, `reverse`, `set`, `shuffle`,
     * `slice`, `sort`, `sortBy`, `sortByAll`, `sortByOrder`, `splice`, `spread`,
     * `take`, `takeRight`, `takeRightWhile`, `takeWhile`, `tap`, `throttle`,
     * `thru`, `times`, `toArray`, `toPlainObject`, `transform`, `union`, `uniq`,
     * `unshift`, `unzip`, `unzipWith`, `values`, `valuesIn`, `where`, `without`,
     * `wrap`, `xor`, `zip`, `zipObject`, `zipWith`
     *
     * The wrapper methods that are **not** chainable by default are:
     * `add`, `attempt`, `camelCase`, `capitalize`, `clone`, `cloneDeep`, `deburr`,
     * `endsWith`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`, `findKey`,
     * `findLast`, `findLastIndex`, `findLastKey`, `findWhere`, `first`, `get`,
     * `gt`, `gte`, `has`, `identity`, `includes`, `indexOf`, `inRange`, `isArguments`,
     * `isArray`, `isBoolean`, `isDate`, `isElement`, `isEmpty`, `isEqual`, `isError`,
     * `isFinite` `isFunction`, `isMatch`, `isNative`, `isNaN`, `isNull`, `isNumber`,
     * `isObject`, `isPlainObject`, `isRegExp`, `isString`, `isUndefined`,
     * `isTypedArray`, `join`, `kebabCase`, `last`, `lastIndexOf`, `lt`, `lte`,
     * `max`, `min`, `noConflict`, `noop`, `now`, `pad`, `padLeft`, `padRight`,
     * `parseInt`, `pop`, `random`, `reduce`, `reduceRight`, `repeat`, `result`,
     * `runInContext`, `shift`, `size`, `snakeCase`, `some`, `sortedIndex`,
     * `sortedLastIndex`, `startCase`, `startsWith`, `sum`, `template`, `trim`,
     * `trimLeft`, `trimRight`, `trunc`, `unescape`, `uniqueId`, `value`, and `words`
     *
     * The wrapper method `sample` will return a wrapped value when `n` is provided,
     * otherwise an unwrapped value is returned.
     *
     * @name _
     * @constructor
     * @category Chain
     * @param {*} value The value to wrap in a `lodash` instance.
     * @returns {Object} Returns the new `lodash` wrapper instance.
     * @example
     *
     * var wrapped = _([1, 2, 3]);
     *
     * // returns an unwrapped value
     * wrapped.reduce(function(total, n) {
     *   return total + n;
     * });
     * // => 6
     *
     * // returns a wrapped value
     * var squares = wrapped.map(function(n) {
     *   return n * n;
     * });
     *
     * _.isArray(squares);
     * // => false
     *
     * _.isArray(squares.value());
     * // => true
     */
    function lodash(value) {
      if (isObjectLike(value) && !isArray(value) && !(value instanceof LazyWrapper)) {
        if (value instanceof LodashWrapper) {
          return value;
        }
        if (hasOwnProperty.call(value, '__chain__') && hasOwnProperty.call(value, '__wrapped__')) {
          return wrapperClone(value);
        }
      }
      return new LodashWrapper(value);
    }

    /**
     * The function whose prototype all chaining wrappers inherit from.
     *
     * @private
     */
    function baseLodash() {
      // No operation performed.
    }

    /**
     * The base constructor for creating `lodash` wrapper objects.
     *
     * @private
     * @param {*} value The value to wrap.
     * @param {boolean} [chainAll] Enable chaining for all wrapper methods.
     * @param {Array} [actions=[]] Actions to peform to resolve the unwrapped value.
     */
    function LodashWrapper(value, chainAll, actions) {
      this.__wrapped__ = value;
      this.__actions__ = actions || [];
      this.__chain__ = !!chainAll;
    }

    /**
     * An object environment feature flags.
     *
     * @static
     * @memberOf _
     * @type Object
     */
    var support = lodash.support = {};

    (function(x) {
      var Ctor = function() { this.x = x; },
          object = { '0': x, 'length': x },
          props = [];

      Ctor.prototype = { 'valueOf': x, 'y': x };
      for (var key in new Ctor) { props.push(key); }

      /**
       * Detect if the DOM is supported.
       *
       * @memberOf _.support
       * @type boolean
       */
      try {
        support.dom = document.createDocumentFragment().nodeType === 11;
      } catch(e) {
        support.dom = false;
      }
    }(1, 0));

    /**
     * By default, the template delimiters used by lodash are like those in
     * embedded Ruby (ERB). Change the following template settings to use
     * alternative delimiters.
     *
     * @static
     * @memberOf _
     * @type Object
     */
    lodash.templateSettings = {

      /**
       * Used to detect `data` property values to be HTML-escaped.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'escape': reEscape,

      /**
       * Used to detect code to be evaluated.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'evaluate': reEvaluate,

      /**
       * Used to detect `data` property values to inject.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'interpolate': reInterpolate,

      /**
       * Used to reference the data object in the template text.
       *
       * @memberOf _.templateSettings
       * @type string
       */
      'variable': '',

      /**
       * Used to import variables into the compiled template.
       *
       * @memberOf _.templateSettings
       * @type Object
       */
      'imports': {

        /**
         * A reference to the `lodash` function.
         *
         * @memberOf _.templateSettings.imports
         * @type Function
         */
        '_': lodash
      }
    };

    /*------------------------------------------------------------------------*/

    /**
     * Creates a lazy wrapper object which wraps `value` to enable lazy evaluation.
     *
     * @private
     * @param {*} value The value to wrap.
     */
    function LazyWrapper(value) {
      this.__wrapped__ = value;
      this.__actions__ = null;
      this.__dir__ = 1;
      this.__dropCount__ = 0;
      this.__filtered__ = false;
      this.__iteratees__ = null;
      this.__takeCount__ = POSITIVE_INFINITY;
      this.__views__ = null;
    }

    /**
     * Creates a clone of the lazy wrapper object.
     *
     * @private
     * @name clone
     * @memberOf LazyWrapper
     * @returns {Object} Returns the cloned `LazyWrapper` object.
     */
    function lazyClone() {
      var actions = this.__actions__,
          iteratees = this.__iteratees__,
          views = this.__views__,
          result = new LazyWrapper(this.__wrapped__);

      result.__actions__ = actions ? arrayCopy(actions) : null;
      result.__dir__ = this.__dir__;
      result.__filtered__ = this.__filtered__;
      result.__iteratees__ = iteratees ? arrayCopy(iteratees) : null;
      result.__takeCount__ = this.__takeCount__;
      result.__views__ = views ? arrayCopy(views) : null;
      return result;
    }

    /**
     * Reverses the direction of lazy iteration.
     *
     * @private
     * @name reverse
     * @memberOf LazyWrapper
     * @returns {Object} Returns the new reversed `LazyWrapper` object.
     */
    function lazyReverse() {
      if (this.__filtered__) {
        var result = new LazyWrapper(this);
        result.__dir__ = -1;
        result.__filtered__ = true;
      } else {
        result = this.clone();
        result.__dir__ *= -1;
      }
      return result;
    }

    /**
     * Extracts the unwrapped value from its lazy wrapper.
     *
     * @private
     * @name value
     * @memberOf LazyWrapper
     * @returns {*} Returns the unwrapped value.
     */
    function lazyValue() {
      var array = this.__wrapped__.value();
      if (!isArray(array)) {
        return baseWrapperValue(array, this.__actions__);
      }
      var dir = this.__dir__,
          isRight = dir < 0,
          view = getView(0, array.length, this.__views__),
          start = view.start,
          end = view.end,
          length = end - start,
          index = isRight ? end : (start - 1),
          takeCount = nativeMin(length, this.__takeCount__),
          iteratees = this.__iteratees__,
          iterLength = iteratees ? iteratees.length : 0,
          resIndex = 0,
          result = [];

      outer:
      while (length-- && resIndex < takeCount) {
        index += dir;

        var iterIndex = -1,
            value = array[index];

        while (++iterIndex < iterLength) {
          var data = iteratees[iterIndex],
              iteratee = data.iteratee,
              type = data.type;

          if (type == LAZY_DROP_WHILE_FLAG) {
            if (data.done && (isRight ? (index > data.index) : (index < data.index))) {
              data.count = 0;
              data.done = false;
            }
            data.index = index;
            if (!data.done) {
              var limit = data.limit;
              if (!(data.done = limit > -1 ? (data.count++ >= limit) : !iteratee(value))) {
                continue outer;
              }
            }
          } else {
            var computed = iteratee(value);
            if (type == LAZY_MAP_FLAG) {
              value = computed;
            } else if (!computed) {
              if (type == LAZY_FILTER_FLAG) {
                continue outer;
              } else {
                break outer;
              }
            }
          }
        }
        result[resIndex++] = value;
      }
      return result;
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates a cache object to store key/value pairs.
     *
     * @private
     * @static
     * @name Cache
     * @memberOf _.memoize
     */
    function MapCache() {
      this.__data__ = {};
    }

    /**
     * Removes `key` and its value from the cache.
     *
     * @private
     * @name delete
     * @memberOf _.memoize.Cache
     * @param {string} key The key of the value to remove.
     * @returns {boolean} Returns `true` if the entry was removed successfully, else `false`.
     */
    function mapDelete(key) {
      return this.has(key) && delete this.__data__[key];
    }

    /**
     * Gets the cached value for `key`.
     *
     * @private
     * @name get
     * @memberOf _.memoize.Cache
     * @param {string} key The key of the value to get.
     * @returns {*} Returns the cached value.
     */
    function mapGet(key) {
      return key == '__proto__' ? undefined : this.__data__[key];
    }

    /**
     * Checks if a cached value for `key` exists.
     *
     * @private
     * @name has
     * @memberOf _.memoize.Cache
     * @param {string} key The key of the entry to check.
     * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
     */
    function mapHas(key) {
      return key != '__proto__' && hasOwnProperty.call(this.__data__, key);
    }

    /**
     * Sets `value` to `key` of the cache.
     *
     * @private
     * @name set
     * @memberOf _.memoize.Cache
     * @param {string} key The key of the value to cache.
     * @param {*} value The value to cache.
     * @returns {Object} Returns the cache object.
     */
    function mapSet(key, value) {
      if (key != '__proto__') {
        this.__data__[key] = value;
      }
      return this;
    }

    /*------------------------------------------------------------------------*/

    /**
     *
     * Creates a cache object to store unique values.
     *
     * @private
     * @param {Array} [values] The values to cache.
     */
    function SetCache(values) {
      var length = values ? values.length : 0;

      this.data = { 'hash': nativeCreate(null), 'set': new Set };
      while (length--) {
        this.push(values[length]);
      }
    }

    /**
     * Checks if `value` is in `cache` mimicking the return signature of
     * `_.indexOf` by returning `0` if the value is found, else `-1`.
     *
     * @private
     * @param {Object} cache The cache to search.
     * @param {*} value The value to search for.
     * @returns {number} Returns `0` if `value` is found, else `-1`.
     */
    function cacheIndexOf(cache, value) {
      var data = cache.data,
          result = (typeof value == 'string' || isObject(value)) ? data.set.has(value) : data.hash[value];

      return result ? 0 : -1;
    }

    /**
     * Adds `value` to the cache.
     *
     * @private
     * @name push
     * @memberOf SetCache
     * @param {*} value The value to cache.
     */
    function cachePush(value) {
      var data = this.data;
      if (typeof value == 'string' || isObject(value)) {
        data.set.add(value);
      } else {
        data.hash[value] = true;
      }
    }

    /*------------------------------------------------------------------------*/

    /**
     * Copies the values of `source` to `array`.
     *
     * @private
     * @param {Array} source The array to copy values from.
     * @param {Array} [array=[]] The array to copy values to.
     * @returns {Array} Returns `array`.
     */
    function arrayCopy(source, array) {
      var index = -1,
          length = source.length;

      array || (array = Array(length));
      while (++index < length) {
        array[index] = source[index];
      }
      return array;
    }

    /**
     * A specialized version of `_.forEach` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array} Returns `array`.
     */
    function arrayEach(array, iteratee) {
      var index = -1,
          length = array.length;

      while (++index < length) {
        if (iteratee(array[index], index, array) === false) {
          break;
        }
      }
      return array;
    }

    /**
     * A specialized version of `_.forEachRight` for arrays without support for
     * callback shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array} Returns `array`.
     */
    function arrayEachRight(array, iteratee) {
      var length = array.length;

      while (length--) {
        if (iteratee(array[length], length, array) === false) {
          break;
        }
      }
      return array;
    }

    /**
     * A specialized version of `_.every` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {boolean} Returns `true` if all elements pass the predicate check,
     *  else `false`.
     */
    function arrayEvery(array, predicate) {
      var index = -1,
          length = array.length;

      while (++index < length) {
        if (!predicate(array[index], index, array)) {
          return false;
        }
      }
      return true;
    }

    /**
     * A specialized version of `baseExtremum` for arrays which invokes `iteratee`
     * with one argument: (value).
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {Function} comparator The function used to compare values.
     * @param {*} exValue The initial extremum value.
     * @returns {*} Returns the extremum value.
     */
    function arrayExtremum(array, iteratee, comparator, exValue) {
      var index = -1,
          length = array.length,
          computed = exValue,
          result = computed;

      while (++index < length) {
        var value = array[index],
            current = +iteratee(value);

        if (comparator(current, computed)) {
          computed = current;
          result = value;
        }
      }
      return result;
    }

    /**
     * A specialized version of `_.filter` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {Array} Returns the new filtered array.
     */
    function arrayFilter(array, predicate) {
      var index = -1,
          length = array.length,
          resIndex = -1,
          result = [];

      while (++index < length) {
        var value = array[index];
        if (predicate(value, index, array)) {
          result[++resIndex] = value;
        }
      }
      return result;
    }

    /**
     * A specialized version of `_.map` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array} Returns the new mapped array.
     */
    function arrayMap(array, iteratee) {
      var index = -1,
          length = array.length,
          result = Array(length);

      while (++index < length) {
        result[index] = iteratee(array[index], index, array);
      }
      return result;
    }

    /**
     * A specialized version of `_.reduce` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {*} [accumulator] The initial value.
     * @param {boolean} [initFromArray] Specify using the first element of `array`
     *  as the initial value.
     * @returns {*} Returns the accumulated value.
     */
    function arrayReduce(array, iteratee, accumulator, initFromArray) {
      var index = -1,
          length = array.length;

      if (initFromArray && length) {
        accumulator = array[++index];
      }
      while (++index < length) {
        accumulator = iteratee(accumulator, array[index], index, array);
      }
      return accumulator;
    }

    /**
     * A specialized version of `_.reduceRight` for arrays without support for
     * callback shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {*} [accumulator] The initial value.
     * @param {boolean} [initFromArray] Specify using the last element of `array`
     *  as the initial value.
     * @returns {*} Returns the accumulated value.
     */
    function arrayReduceRight(array, iteratee, accumulator, initFromArray) {
      var length = array.length;
      if (initFromArray && length) {
        accumulator = array[--length];
      }
      while (length--) {
        accumulator = iteratee(accumulator, array[length], length, array);
      }
      return accumulator;
    }

    /**
     * A specialized version of `_.some` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {boolean} Returns `true` if any element passes the predicate check,
     *  else `false`.
     */
    function arraySome(array, predicate) {
      var index = -1,
          length = array.length;

      while (++index < length) {
        if (predicate(array[index], index, array)) {
          return true;
        }
      }
      return false;
    }

    /**
     * A specialized version of `_.sum` for arrays without support for iteratees.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @returns {number} Returns the sum.
     */
    function arraySum(array) {
      var length = array.length,
          result = 0;

      while (length--) {
        result += +array[length] || 0;
      }
      return result;
    }

    /**
     * Used by `_.defaults` to customize its `_.assign` use.
     *
     * @private
     * @param {*} objectValue The destination object property value.
     * @param {*} sourceValue The source object property value.
     * @returns {*} Returns the value to assign to the destination object.
     */
    function assignDefaults(objectValue, sourceValue) {
      return objectValue === undefined ? sourceValue : objectValue;
    }

    /**
     * Used by `_.template` to customize its `_.assign` use.
     *
     * **Note:** This function is like `assignDefaults` except that it ignores
     * inherited property values when checking if a property is `undefined`.
     *
     * @private
     * @param {*} objectValue The destination object property value.
     * @param {*} sourceValue The source object property value.
     * @param {string} key The key associated with the object and source values.
     * @param {Object} object The destination object.
     * @returns {*} Returns the value to assign to the destination object.
     */
    function assignOwnDefaults(objectValue, sourceValue, key, object) {
      return (objectValue === undefined || !hasOwnProperty.call(object, key))
        ? sourceValue
        : objectValue;
    }

    /**
     * A specialized version of `_.assign` for customizing assigned values without
     * support for argument juggling, multiple sources, and `this` binding `customizer`
     * functions.
     *
     * @private
     * @param {Object} object The destination object.
     * @param {Object} source The source object.
     * @param {Function} customizer The function to customize assigned values.
     * @returns {Object} Returns `object`.
     */
    function assignWith(object, source, customizer) {
      var index = -1,
          props = keys(source),
          length = props.length;

      while (++index < length) {
        var key = props[index],
            value = object[key],
            result = customizer(value, source[key], key, object, source);

        if ((result === result ? (result !== value) : (value === value)) ||
            (value === undefined && !(key in object))) {
          object[key] = result;
        }
      }
      return object;
    }

    /**
     * The base implementation of `_.assign` without support for argument juggling,
     * multiple sources, and `customizer` functions.
     *
     * @private
     * @param {Object} object The destination object.
     * @param {Object} source The source object.
     * @returns {Object} Returns `object`.
     */
    function baseAssign(object, source) {
      return source == null
        ? object
        : baseCopy(source, keys(source), object);
    }

    /**
     * The base implementation of `_.at` without support for string collections
     * and individual key arguments.
     *
     * @private
     * @param {Array|Object} collection The collection to iterate over.
     * @param {number[]|string[]} props The property names or indexes of elements to pick.
     * @returns {Array} Returns the new array of picked elements.
     */
    function baseAt(collection, props) {
      var index = -1,
          isNil = collection == null,
          isArr = !isNil && isArrayLike(collection),
          length = isArr ? collection.length : 0,
          propsLength = props.length,
          result = Array(propsLength);

      while(++index < propsLength) {
        var key = props[index];
        if (isArr) {
          result[index] = isIndex(key, length) ? collection[key] : undefined;
        } else {
          result[index] = isNil ? undefined : collection[key];
        }
      }
      return result;
    }

    /**
     * Copies properties of `source` to `object`.
     *
     * @private
     * @param {Object} source The object to copy properties from.
     * @param {Array} props The property names to copy.
     * @param {Object} [object={}] The object to copy properties to.
     * @returns {Object} Returns `object`.
     */
    function baseCopy(source, props, object) {
      object || (object = {});

      var index = -1,
          length = props.length;

      while (++index < length) {
        var key = props[index];
        object[key] = source[key];
      }
      return object;
    }

    /**
     * The base implementation of `_.callback` which supports specifying the
     * number of arguments to provide to `func`.
     *
     * @private
     * @param {*} [func=_.identity] The value to convert to a callback.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @param {number} [argCount] The number of arguments to provide to `func`.
     * @returns {Function} Returns the callback.
     */
    function baseCallback(func, thisArg, argCount) {
      var type = typeof func;
      if (type == 'function') {
        return thisArg === undefined
          ? func
          : bindCallback(func, thisArg, argCount);
      }
      if (func == null) {
        return identity;
      }
      if (type == 'object') {
        return baseMatches(func);
      }
      return thisArg === undefined
        ? property(func)
        : baseMatchesProperty(func, thisArg);
    }

    /**
     * The base implementation of `_.clone` without support for argument juggling
     * and `this` binding `customizer` functions.
     *
     * @private
     * @param {*} value The value to clone.
     * @param {boolean} [isDeep] Specify a deep clone.
     * @param {Function} [customizer] The function to customize cloning values.
     * @param {string} [key] The key of `value`.
     * @param {Object} [object] The object `value` belongs to.
     * @param {Array} [stackA=[]] Tracks traversed source objects.
     * @param {Array} [stackB=[]] Associates clones with source counterparts.
     * @returns {*} Returns the cloned value.
     */
    function baseClone(value, isDeep, customizer, key, object, stackA, stackB) {
      var result;
      if (customizer) {
        result = object ? customizer(value, key, object) : customizer(value);
      }
      if (result !== undefined) {
        return result;
      }
      if (!isObject(value)) {
        return value;
      }
      var isArr = isArray(value);
      if (isArr) {
        result = initCloneArray(value);
        if (!isDeep) {
          return arrayCopy(value, result);
        }
      } else {
        var tag = objToString.call(value),
            isFunc = tag == funcTag;

        if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
          result = initCloneObject(isFunc ? {} : value);
          if (!isDeep) {
            return baseAssign(result, value);
          }
        } else {
          return cloneableTags[tag]
            ? initCloneByTag(value, tag, isDeep)
            : (object ? value : {});
        }
      }
      // Check for circular references and return corresponding clone.
      stackA || (stackA = []);
      stackB || (stackB = []);

      var length = stackA.length;
      while (length--) {
        if (stackA[length] == value) {
          return stackB[length];
        }
      }
      // Add the source value to the stack of traversed objects and associate it with its clone.
      stackA.push(value);
      stackB.push(result);

      // Recursively populate clone (susceptible to call stack limits).
      (isArr ? arrayEach : baseForOwn)(value, function(subValue, key) {
        result[key] = baseClone(subValue, isDeep, customizer, key, value, stackA, stackB);
      });
      return result;
    }

    /**
     * The base implementation of `_.create` without support for assigning
     * properties to the created object.
     *
     * @private
     * @param {Object} prototype The object to inherit from.
     * @returns {Object} Returns the new object.
     */
    var baseCreate = (function() {
      function object() {}
      return function(prototype) {
        if (isObject(prototype)) {
          object.prototype = prototype;
          var result = new object;
          object.prototype = null;
        }
        return result || {};
      };
    }());

    /**
     * The base implementation of `_.delay` and `_.defer` which accepts an index
     * of where to slice the arguments to provide to `func`.
     *
     * @private
     * @param {Function} func The function to delay.
     * @param {number} wait The number of milliseconds to delay invocation.
     * @param {Object} args The arguments provide to `func`.
     * @returns {number} Returns the timer id.
     */
    function baseDelay(func, wait, args) {
      if (typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      return setTimeout(function() { func.apply(undefined, args); }, wait);
    }

    /**
     * The base implementation of `_.difference` which accepts a single array
     * of values to exclude.
     *
     * @private
     * @param {Array} array The array to inspect.
     * @param {Array} values The values to exclude.
     * @returns {Array} Returns the new array of filtered values.
     */
    function baseDifference(array, values) {
      var length = array ? array.length : 0,
          result = [];

      if (!length) {
        return result;
      }
      var index = -1,
          indexOf = getIndexOf(),
          isCommon = indexOf == baseIndexOf,
          cache = (isCommon && values.length >= 200) ? createCache(values) : null,
          valuesLength = values.length;

      if (cache) {
        indexOf = cacheIndexOf;
        isCommon = false;
        values = cache;
      }
      outer:
      while (++index < length) {
        var value = array[index];

        if (isCommon && value === value) {
          var valuesIndex = valuesLength;
          while (valuesIndex--) {
            if (values[valuesIndex] === value) {
              continue outer;
            }
          }
          result.push(value);
        }
        else if (indexOf(values, value, 0) < 0) {
          result.push(value);
        }
      }
      return result;
    }

    /**
     * The base implementation of `_.forEach` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array|Object|string} Returns `collection`.
     */
    var baseEach = createBaseEach(baseForOwn);

    /**
     * The base implementation of `_.forEachRight` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array|Object|string} Returns `collection`.
     */
    var baseEachRight = createBaseEach(baseForOwnRight, true);

    /**
     * The base implementation of `_.every` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {boolean} Returns `true` if all elements pass the predicate check,
     *  else `false`
     */
    function baseEvery(collection, predicate) {
      var result = true;
      baseEach(collection, function(value, index, collection) {
        result = !!predicate(value, index, collection);
        return result;
      });
      return result;
    }

    /**
     * Gets the extremum value of `collection` invoking `iteratee` for each value
     * in `collection` to generate the criterion by which the value is ranked.
     * The `iteratee` is invoked with three arguments: (value, index|key, collection).
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {Function} comparator The function used to compare values.
     * @param {*} exValue The initial extremum value.
     * @returns {*} Returns the extremum value.
     */
    function baseExtremum(collection, iteratee, comparator, exValue) {
      var computed = exValue,
          result = computed;

      baseEach(collection, function(value, index, collection) {
        var current = +iteratee(value, index, collection);
        if (comparator(current, computed) || (current === exValue && current === result)) {
          computed = current;
          result = value;
        }
      });
      return result;
    }

    /**
     * The base implementation of `_.fill` without an iteratee call guard.
     *
     * @private
     * @param {Array} array The array to fill.
     * @param {*} value The value to fill `array` with.
     * @param {number} [start=0] The start position.
     * @param {number} [end=array.length] The end position.
     * @returns {Array} Returns `array`.
     */
    function baseFill(array, value, start, end) {
      var length = array.length;

      start = start == null ? 0 : (+start || 0);
      if (start < 0) {
        start = -start > length ? 0 : (length + start);
      }
      end = (end === undefined || end > length) ? length : (+end || 0);
      if (end < 0) {
        end += length;
      }
      length = start > end ? 0 : (end >>> 0);
      start >>>= 0;

      while (start < length) {
        array[start++] = value;
      }
      return array;
    }

    /**
     * The base implementation of `_.filter` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {Array} Returns the new filtered array.
     */
    function baseFilter(collection, predicate) {
      var result = [];
      baseEach(collection, function(value, index, collection) {
        if (predicate(value, index, collection)) {
          result.push(value);
        }
      });
      return result;
    }

    /**
     * The base implementation of `_.find`, `_.findLast`, `_.findKey`, and `_.findLastKey`,
     * without support for callback shorthands and `this` binding, which iterates
     * over `collection` using the provided `eachFunc`.
     *
     * @private
     * @param {Array|Object|string} collection The collection to search.
     * @param {Function} predicate The function invoked per iteration.
     * @param {Function} eachFunc The function to iterate over `collection`.
     * @param {boolean} [retKey] Specify returning the key of the found element
     *  instead of the element itself.
     * @returns {*} Returns the found element or its key, else `undefined`.
     */
    function baseFind(collection, predicate, eachFunc, retKey) {
      var result;
      eachFunc(collection, function(value, key, collection) {
        if (predicate(value, key, collection)) {
          result = retKey ? key : value;
          return false;
        }
      });
      return result;
    }

    /**
     * The base implementation of `_.flatten` with added support for restricting
     * flattening and specifying the start index.
     *
     * @private
     * @param {Array} array The array to flatten.
     * @param {boolean} [isDeep] Specify a deep flatten.
     * @param {boolean} [isStrict] Restrict flattening to arrays-like objects.
     * @returns {Array} Returns the new flattened array.
     */
    function baseFlatten(array, isDeep, isStrict) {
      var index = -1,
          length = array.length,
          resIndex = -1,
          result = [];

      while (++index < length) {
        var value = array[index];
        if (isObjectLike(value) && isArrayLike(value) &&
            (isStrict || isArray(value) || isArguments(value))) {
          if (isDeep) {
            // Recursively flatten arrays (susceptible to call stack limits).
            value = baseFlatten(value, isDeep, isStrict);
          }
          var valIndex = -1,
              valLength = value.length;

          while (++valIndex < valLength) {
            result[++resIndex] = value[valIndex];
          }
        } else if (!isStrict) {
          result[++resIndex] = value;
        }
      }
      return result;
    }

    /**
     * The base implementation of `baseForIn` and `baseForOwn` which iterates
     * over `object` properties returned by `keysFunc` invoking `iteratee` for
     * each property. Iteratee functions may exit iteration early by explicitly
     * returning `false`.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {Function} keysFunc The function to get the keys of `object`.
     * @returns {Object} Returns `object`.
     */
    var baseFor = createBaseFor();

    /**
     * This function is like `baseFor` except that it iterates over properties
     * in the opposite order.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {Function} keysFunc The function to get the keys of `object`.
     * @returns {Object} Returns `object`.
     */
    var baseForRight = createBaseFor(true);

    /**
     * The base implementation of `_.forIn` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Object} Returns `object`.
     */
    function baseForIn(object, iteratee) {
      return baseFor(object, iteratee, keysIn);
    }

    /**
     * The base implementation of `_.forOwn` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Object} Returns `object`.
     */
    function baseForOwn(object, iteratee) {
      return baseFor(object, iteratee, keys);
    }

    /**
     * The base implementation of `_.forOwnRight` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Object} Returns `object`.
     */
    function baseForOwnRight(object, iteratee) {
      return baseForRight(object, iteratee, keys);
    }

    /**
     * The base implementation of `_.functions` which creates an array of
     * `object` function property names filtered from those provided.
     *
     * @private
     * @param {Object} object The object to inspect.
     * @param {Array} props The property names to filter.
     * @returns {Array} Returns the new array of filtered property names.
     */
    function baseFunctions(object, props) {
      var index = -1,
          length = props.length,
          resIndex = -1,
          result = [];

      while (++index < length) {
        var key = props[index];
        if (isFunction(object[key])) {
          result[++resIndex] = key;
        }
      }
      return result;
    }

    /**
     * The base implementation of `get` without support for string paths
     * and default values.
     *
     * @private
     * @param {Object} object The object to query.
     * @param {Array} path The path of the property to get.
     * @param {string} [pathKey] The key representation of path.
     * @returns {*} Returns the resolved value.
     */
    function baseGet(object, path, pathKey) {
      if (object == null) {
        return;
      }
      if (pathKey !== undefined && pathKey in toObject(object)) {
        path = [pathKey];
      }
      var index = 0,
          length = path.length;

      while (object != null && index < length) {
        object = object[path[index++]];
      }
      return (index && index == length) ? object : undefined;
    }

    /**
     * The base implementation of `_.isEqual` without support for `this` binding
     * `customizer` functions.
     *
     * @private
     * @param {*} value The value to compare.
     * @param {*} other The other value to compare.
     * @param {Function} [customizer] The function to customize comparing values.
     * @param {boolean} [isLoose] Specify performing partial comparisons.
     * @param {Array} [stackA] Tracks traversed `value` objects.
     * @param {Array} [stackB] Tracks traversed `other` objects.
     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
     */
    function baseIsEqual(value, other, customizer, isLoose, stackA, stackB) {
      if (value === other) {
        return true;
      }
      if (value == null || other == null || (!isObject(value) && !isObjectLike(other))) {
        return value !== value && other !== other;
      }
      return baseIsEqualDeep(value, other, baseIsEqual, customizer, isLoose, stackA, stackB);
    }

    /**
     * A specialized version of `baseIsEqual` for arrays and objects which performs
     * deep comparisons and tracks traversed objects enabling objects with circular
     * references to be compared.
     *
     * @private
     * @param {Object} object The object to compare.
     * @param {Object} other The other object to compare.
     * @param {Function} equalFunc The function to determine equivalents of values.
     * @param {Function} [customizer] The function to customize comparing objects.
     * @param {boolean} [isLoose] Specify performing partial comparisons.
     * @param {Array} [stackA=[]] Tracks traversed `value` objects.
     * @param {Array} [stackB=[]] Tracks traversed `other` objects.
     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
     */
    function baseIsEqualDeep(object, other, equalFunc, customizer, isLoose, stackA, stackB) {
      var objIsArr = isArray(object),
          othIsArr = isArray(other),
          objTag = arrayTag,
          othTag = arrayTag;

      if (!objIsArr) {
        objTag = objToString.call(object);
        if (objTag == argsTag) {
          objTag = objectTag;
        } else if (objTag != objectTag) {
          objIsArr = isTypedArray(object);
        }
      }
      if (!othIsArr) {
        othTag = objToString.call(other);
        if (othTag == argsTag) {
          othTag = objectTag;
        } else if (othTag != objectTag) {
          othIsArr = isTypedArray(other);
        }
      }
      var objIsObj = objTag == objectTag,
          othIsObj = othTag == objectTag,
          isSameTag = objTag == othTag;

      if (isSameTag && !(objIsArr || objIsObj)) {
        return equalByTag(object, other, objTag);
      }
      if (!isLoose) {
        var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
            othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');

        if (objIsWrapped || othIsWrapped) {
          return equalFunc(objIsWrapped ? object.value() : object, othIsWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
        }
      }
      if (!isSameTag) {
        return false;
      }
      // Assume cyclic values are equal.
      // For more information on detecting circular references see https://es5.github.io/#JO.
      stackA || (stackA = []);
      stackB || (stackB = []);

      var length = stackA.length;
      while (length--) {
        if (stackA[length] == object) {
          return stackB[length] == other;
        }
      }
      // Add `object` and `other` to the stack of traversed objects.
      stackA.push(object);
      stackB.push(other);

      var result = (objIsArr ? equalArrays : equalObjects)(object, other, equalFunc, customizer, isLoose, stackA, stackB);

      stackA.pop();
      stackB.pop();

      return result;
    }

    /**
     * The base implementation of `_.isMatch` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Object} object The object to inspect.
     * @param {Array} matchData The propery names, values, and compare flags to match.
     * @param {Function} [customizer] The function to customize comparing objects.
     * @returns {boolean} Returns `true` if `object` is a match, else `false`.
     */
    function baseIsMatch(object, matchData, customizer) {
      var index = matchData.length,
          length = index,
          noCustomizer = !customizer;

      if (object == null) {
        return !length;
      }
      object = toObject(object);
      while (index--) {
        var data = matchData[index];
        if ((noCustomizer && data[2])
              ? data[1] !== object[data[0]]
              : !(data[0] in object)
            ) {
          return false;
        }
      }
      while (++index < length) {
        data = matchData[index];
        var key = data[0],
            objValue = object[key],
            srcValue = data[1];

        if (noCustomizer && data[2]) {
          if (objValue === undefined && !(key in object)) {
            return false;
          }
        } else {
          var result = customizer ? customizer(objValue, srcValue, key) : undefined;
          if (!(result === undefined ? baseIsEqual(srcValue, objValue, customizer, true) : result)) {
            return false;
          }
        }
      }
      return true;
    }

    /**
     * The base implementation of `_.map` without support for callback shorthands
     * and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array} Returns the new mapped array.
     */
    function baseMap(collection, iteratee) {
      var index = -1,
          result = isArrayLike(collection) ? Array(collection.length) : [];

      baseEach(collection, function(value, key, collection) {
        result[++index] = iteratee(value, key, collection);
      });
      return result;
    }

    /**
     * The base implementation of `_.matches` which does not clone `source`.
     *
     * @private
     * @param {Object} source The object of property values to match.
     * @returns {Function} Returns the new function.
     */
    function baseMatches(source) {
      var matchData = getMatchData(source);
      if (matchData.length == 1 && matchData[0][2]) {
        var key = matchData[0][0],
            value = matchData[0][1];

        return function(object) {
          if (object == null) {
            return false;
          }
          return object[key] === value && (value !== undefined || (key in toObject(object)));
        };
      }
      return function(object) {
        return baseIsMatch(object, matchData);
      };
    }

    /**
     * The base implementation of `_.matchesProperty` which does not clone `srcValue`.
     *
     * @private
     * @param {string} path The path of the property to get.
     * @param {*} srcValue The value to compare.
     * @returns {Function} Returns the new function.
     */
    function baseMatchesProperty(path, srcValue) {
      var isArr = isArray(path),
          isCommon = isKey(path) && isStrictComparable(srcValue),
          pathKey = (path + '');

      path = toPath(path);
      return function(object) {
        if (object == null) {
          return false;
        }
        var key = pathKey;
        object = toObject(object);
        if ((isArr || !isCommon) && !(key in object)) {
          object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
          if (object == null) {
            return false;
          }
          key = last(path);
          object = toObject(object);
        }
        return object[key] === srcValue
          ? (srcValue !== undefined || (key in object))
          : baseIsEqual(srcValue, object[key], undefined, true);
      };
    }

    /**
     * The base implementation of `_.merge` without support for argument juggling,
     * multiple sources, and `this` binding `customizer` functions.
     *
     * @private
     * @param {Object} object The destination object.
     * @param {Object} source The source object.
     * @param {Function} [customizer] The function to customize merging properties.
     * @param {Array} [stackA=[]] Tracks traversed source objects.
     * @param {Array} [stackB=[]] Associates values with source counterparts.
     * @returns {Object} Returns `object`.
     */
    function baseMerge(object, source, customizer, stackA, stackB) {
      if (!isObject(object)) {
        return object;
      }
      var isSrcArr = isArrayLike(source) && (isArray(source) || isTypedArray(source)),
          props = isSrcArr ? null : keys(source);

      arrayEach(props || source, function(srcValue, key) {
        if (props) {
          key = srcValue;
          srcValue = source[key];
        }
        if (isObjectLike(srcValue)) {
          stackA || (stackA = []);
          stackB || (stackB = []);
          baseMergeDeep(object, source, key, baseMerge, customizer, stackA, stackB);
        }
        else {
          var value = object[key],
              result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
              isCommon = result === undefined;

          if (isCommon) {
            result = srcValue;
          }
          if ((result !== undefined || (isSrcArr && !(key in object))) &&
              (isCommon || (result === result ? (result !== value) : (value === value)))) {
            object[key] = result;
          }
        }
      });
      return object;
    }

    /**
     * A specialized version of `baseMerge` for arrays and objects which performs
     * deep merges and tracks traversed objects enabling objects with circular
     * references to be merged.
     *
     * @private
     * @param {Object} object The destination object.
     * @param {Object} source The source object.
     * @param {string} key The key of the value to merge.
     * @param {Function} mergeFunc The function to merge values.
     * @param {Function} [customizer] The function to customize merging properties.
     * @param {Array} [stackA=[]] Tracks traversed source objects.
     * @param {Array} [stackB=[]] Associates values with source counterparts.
     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
     */
    function baseMergeDeep(object, source, key, mergeFunc, customizer, stackA, stackB) {
      var length = stackA.length,
          srcValue = source[key];

      while (length--) {
        if (stackA[length] == srcValue) {
          object[key] = stackB[length];
          return;
        }
      }
      var value = object[key],
          result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
          isCommon = result === undefined;

      if (isCommon) {
        result = srcValue;
        if (isArrayLike(srcValue) && (isArray(srcValue) || isTypedArray(srcValue))) {
          result = isArray(value)
            ? value
            : (isArrayLike(value) ? arrayCopy(value) : []);
        }
        else if (isPlainObject(srcValue) || isArguments(srcValue)) {
          result = isArguments(value)
            ? toPlainObject(value)
            : (isPlainObject(value) ? value : {});
        }
        else {
          isCommon = false;
        }
      }
      // Add the source value to the stack of traversed objects and associate
      // it with its merged value.
      stackA.push(srcValue);
      stackB.push(result);

      if (isCommon) {
        // Recursively merge objects and arrays (susceptible to call stack limits).
        object[key] = mergeFunc(result, srcValue, customizer, stackA, stackB);
      } else if (result === result ? (result !== value) : (value === value)) {
        object[key] = result;
      }
    }

    /**
     * The base implementation of `_.property` without support for deep paths.
     *
     * @private
     * @param {string} key The key of the property to get.
     * @returns {Function} Returns the new function.
     */
    function baseProperty(key) {
      return function(object) {
        return object == null ? undefined : object[key];
      };
    }

    /**
     * A specialized version of `baseProperty` which supports deep paths.
     *
     * @private
     * @param {Array|string} path The path of the property to get.
     * @returns {Function} Returns the new function.
     */
    function basePropertyDeep(path) {
      var pathKey = (path + '');
      path = toPath(path);
      return function(object) {
        return baseGet(object, path, pathKey);
      };
    }

    /**
     * The base implementation of `_.pullAt` without support for individual
     * index arguments and capturing the removed elements.
     *
     * @private
     * @param {Array} array The array to modify.
     * @param {number[]} indexes The indexes of elements to remove.
     * @returns {Array} Returns `array`.
     */
    function basePullAt(array, indexes) {
      var length = array ? indexes.length : 0;
      while (length--) {
        var index = indexes[length];
        if (index != previous && isIndex(index)) {
          var previous = index;
          splice.call(array, index, 1);
        }
      }
      return array;
    }

    /**
     * The base implementation of `_.random` without support for argument juggling
     * and returning floating-point numbers.
     *
     * @private
     * @param {number} min The minimum possible value.
     * @param {number} max The maximum possible value.
     * @returns {number} Returns the random number.
     */
    function baseRandom(min, max) {
      return min + floor(nativeRandom() * (max - min + 1));
    }

    /**
     * The base implementation of `_.reduce` and `_.reduceRight` without support
     * for callback shorthands and `this` binding, which iterates over `collection`
     * using the provided `eachFunc`.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {*} accumulator The initial value.
     * @param {boolean} initFromCollection Specify using the first or last element
     *  of `collection` as the initial value.
     * @param {Function} eachFunc The function to iterate over `collection`.
     * @returns {*} Returns the accumulated value.
     */
    function baseReduce(collection, iteratee, accumulator, initFromCollection, eachFunc) {
      eachFunc(collection, function(value, index, collection) {
        accumulator = initFromCollection
          ? (initFromCollection = false, value)
          : iteratee(accumulator, value, index, collection);
      });
      return accumulator;
    }

    /**
     * The base implementation of `setData` without support for hot loop detection.
     *
     * @private
     * @param {Function} func The function to associate metadata with.
     * @param {*} data The metadata.
     * @returns {Function} Returns `func`.
     */
    var baseSetData = !metaMap ? identity : function(func, data) {
      metaMap.set(func, data);
      return func;
    };

    /**
     * The base implementation of `_.slice` without an iteratee call guard.
     *
     * @private
     * @param {Array} array The array to slice.
     * @param {number} [start=0] The start position.
     * @param {number} [end=array.length] The end position.
     * @returns {Array} Returns the slice of `array`.
     */
    function baseSlice(array, start, end) {
      var index = -1,
          length = array.length;

      start = start == null ? 0 : (+start || 0);
      if (start < 0) {
        start = -start > length ? 0 : (length + start);
      }
      end = (end === undefined || end > length) ? length : (+end || 0);
      if (end < 0) {
        end += length;
      }
      length = start > end ? 0 : ((end - start) >>> 0);
      start >>>= 0;

      var result = Array(length);
      while (++index < length) {
        result[index] = array[index + start];
      }
      return result;
    }

    /**
     * The base implementation of `_.some` without support for callback shorthands
     * and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {boolean} Returns `true` if any element passes the predicate check,
     *  else `false`.
     */
    function baseSome(collection, predicate) {
      var result;

      baseEach(collection, function(value, index, collection) {
        result = predicate(value, index, collection);
        return !result;
      });
      return !!result;
    }

    /**
     * The base implementation of `_.sortBy` which uses `comparer` to define
     * the sort order of `array` and replaces criteria objects with their
     * corresponding values.
     *
     * @private
     * @param {Array} array The array to sort.
     * @param {Function} comparer The function to define sort order.
     * @returns {Array} Returns `array`.
     */
    function baseSortBy(array, comparer) {
      var length = array.length;

      array.sort(comparer);
      while (length--) {
        array[length] = array[length].value;
      }
      return array;
    }

    /**
     * The base implementation of `_.sortByOrder` without param guards.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
     * @param {boolean[]} orders The sort orders of `iteratees`.
     * @returns {Array} Returns the new sorted array.
     */
    function baseSortByOrder(collection, iteratees, orders) {
      var callback = getCallback(),
          index = -1;

      iteratees = arrayMap(iteratees, function(iteratee) { return callback(iteratee); });

      var result = baseMap(collection, function(value) {
        var criteria = arrayMap(iteratees, function(iteratee) { return iteratee(value); });
        return { 'criteria': criteria, 'index': ++index, 'value': value };
      });

      return baseSortBy(result, function(object, other) {
        return compareMultiple(object, other, orders);
      });
    }

    /**
     * The base implementation of `_.sum` without support for callback shorthands
     * and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {number} Returns the sum.
     */
    function baseSum(collection, iteratee) {
      var result = 0;
      baseEach(collection, function(value, index, collection) {
        result += +iteratee(value, index, collection) || 0;
      });
      return result;
    }

    /**
     * The base implementation of `_.uniq` without support for callback shorthands
     * and `this` binding.
     *
     * @private
     * @param {Array} array The array to inspect.
     * @param {Function} [iteratee] The function invoked per iteration.
     * @returns {Array} Returns the new duplicate-value-free array.
     */
    function baseUniq(array, iteratee) {
      var index = -1,
          indexOf = getIndexOf(),
          length = array.length,
          isCommon = indexOf == baseIndexOf,
          isLarge = isCommon && length >= 200,
          seen = isLarge ? createCache() : null,
          result = [];

      if (seen) {
        indexOf = cacheIndexOf;
        isCommon = false;
      } else {
        isLarge = false;
        seen = iteratee ? [] : result;
      }
      outer:
      while (++index < length) {
        var value = array[index],
            computed = iteratee ? iteratee(value, index, array) : value;

        if (isCommon && value === value) {
          var seenIndex = seen.length;
          while (seenIndex--) {
            if (seen[seenIndex] === computed) {
              continue outer;
            }
          }
          if (iteratee) {
            seen.push(computed);
          }
          result.push(value);
        }
        else if (indexOf(seen, computed, 0) < 0) {
          if (iteratee || isLarge) {
            seen.push(computed);
          }
          result.push(value);
        }
      }
      return result;
    }

    /**
     * The base implementation of `_.values` and `_.valuesIn` which creates an
     * array of `object` property values corresponding to the property names
     * of `props`.
     *
     * @private
     * @param {Object} object The object to query.
     * @param {Array} props The property names to get values for.
     * @returns {Object} Returns the array of property values.
     */
    function baseValues(object, props) {
      var index = -1,
          length = props.length,
          result = Array(length);

      while (++index < length) {
        result[index] = object[props[index]];
      }
      return result;
    }

    /**
     * The base implementation of `_.dropRightWhile`, `_.dropWhile`, `_.takeRightWhile`,
     * and `_.takeWhile` without support for callback shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to query.
     * @param {Function} predicate The function invoked per iteration.
     * @param {boolean} [isDrop] Specify dropping elements instead of taking them.
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Array} Returns the slice of `array`.
     */
    function baseWhile(array, predicate, isDrop, fromRight) {
      var length = array.length,
          index = fromRight ? length : -1;

      while ((fromRight ? index-- : ++index < length) && predicate(array[index], index, array)) {}
      return isDrop
        ? baseSlice(array, (fromRight ? 0 : index), (fromRight ? index + 1 : length))
        : baseSlice(array, (fromRight ? index + 1 : 0), (fromRight ? length : index));
    }

    /**
     * The base implementation of `wrapperValue` which returns the result of
     * performing a sequence of actions on the unwrapped `value`, where each
     * successive action is supplied the return value of the previous.
     *
     * @private
     * @param {*} value The unwrapped value.
     * @param {Array} actions Actions to peform to resolve the unwrapped value.
     * @returns {*} Returns the resolved value.
     */
    function baseWrapperValue(value, actions) {
      var result = value;
      if (result instanceof LazyWrapper) {
        result = result.value();
      }
      var index = -1,
          length = actions.length;

      while (++index < length) {
        var args = [result],
            action = actions[index];

        push.apply(args, action.args);
        result = action.func.apply(action.thisArg, args);
      }
      return result;
    }

    /**
     * Performs a binary search of `array` to determine the index at which `value`
     * should be inserted into `array` in order to maintain its sort order.
     *
     * @private
     * @param {Array} array The sorted array to inspect.
     * @param {*} value The value to evaluate.
     * @param {boolean} [retHighest] Specify returning the highest qualified index.
     * @returns {number} Returns the index at which `value` should be inserted
     *  into `array`.
     */
    function binaryIndex(array, value, retHighest) {
      var low = 0,
          high = array ? array.length : low;

      if (typeof value == 'number' && value === value && high <= HALF_MAX_ARRAY_LENGTH) {
        while (low < high) {
          var mid = (low + high) >>> 1,
              computed = array[mid];

          if ((retHighest ? (computed <= value) : (computed < value)) && computed !== null) {
            low = mid + 1;
          } else {
            high = mid;
          }
        }
        return high;
      }
      return binaryIndexBy(array, value, identity, retHighest);
    }

    /**
     * This function is like `binaryIndex` except that it invokes `iteratee` for
     * `value` and each element of `array` to compute their sort ranking. The
     * iteratee is invoked with one argument; (value).
     *
     * @private
     * @param {Array} array The sorted array to inspect.
     * @param {*} value The value to evaluate.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {boolean} [retHighest] Specify returning the highest qualified index.
     * @returns {number} Returns the index at which `value` should be inserted
     *  into `array`.
     */
    function binaryIndexBy(array, value, iteratee, retHighest) {
      value = iteratee(value);

      var low = 0,
          high = array ? array.length : 0,
          valIsNaN = value !== value,
          valIsNull = value === null,
          valIsUndef = value === undefined;

      while (low < high) {
        var mid = floor((low + high) / 2),
            computed = iteratee(array[mid]),
            isDef = computed !== undefined,
            isReflexive = computed === computed;

        if (valIsNaN) {
          var setLow = isReflexive || retHighest;
        } else if (valIsNull) {
          setLow = isReflexive && isDef && (retHighest || computed != null);
        } else if (valIsUndef) {
          setLow = isReflexive && (retHighest || isDef);
        } else if (computed == null) {
          setLow = false;
        } else {
          setLow = retHighest ? (computed <= value) : (computed < value);
        }
        if (setLow) {
          low = mid + 1;
        } else {
          high = mid;
        }
      }
      return nativeMin(high, MAX_ARRAY_INDEX);
    }

    /**
     * A specialized version of `baseCallback` which only supports `this` binding
     * and specifying the number of arguments to provide to `func`.
     *
     * @private
     * @param {Function} func The function to bind.
     * @param {*} thisArg The `this` binding of `func`.
     * @param {number} [argCount] The number of arguments to provide to `func`.
     * @returns {Function} Returns the callback.
     */
    function bindCallback(func, thisArg, argCount) {
      if (typeof func != 'function') {
        return identity;
      }
      if (thisArg === undefined) {
        return func;
      }
      switch (argCount) {
        case 1: return function(value) {
          return func.call(thisArg, value);
        };
        case 3: return function(value, index, collection) {
          return func.call(thisArg, value, index, collection);
        };
        case 4: return function(accumulator, value, index, collection) {
          return func.call(thisArg, accumulator, value, index, collection);
        };
        case 5: return function(value, other, key, object, source) {
          return func.call(thisArg, value, other, key, object, source);
        };
      }
      return function() {
        return func.apply(thisArg, arguments);
      };
    }

    /**
     * Creates a clone of the given array buffer.
     *
     * @private
     * @param {ArrayBuffer} buffer The array buffer to clone.
     * @returns {ArrayBuffer} Returns the cloned array buffer.
     */
    function bufferClone(buffer) {
      return bufferSlice.call(buffer, 0);
    }
    if (!bufferSlice) {
      // PhantomJS has `ArrayBuffer` and `Uint8Array` but not `Float64Array`.
      bufferClone = !(ArrayBuffer && Uint8Array) ? constant(null) : function(buffer) {
        var byteLength = buffer.byteLength,
            floatLength = Float64Array ? floor(byteLength / FLOAT64_BYTES_PER_ELEMENT) : 0,
            offset = floatLength * FLOAT64_BYTES_PER_ELEMENT,
            result = new ArrayBuffer(byteLength);

        if (floatLength) {
          var view = new Float64Array(result, 0, floatLength);
          view.set(new Float64Array(buffer, 0, floatLength));
        }
        if (byteLength != offset) {
          view = new Uint8Array(result, offset);
          view.set(new Uint8Array(buffer, offset));
        }
        return result;
      };
    }

    /**
     * Creates an array that is the composition of partially applied arguments,
     * placeholders, and provided arguments into a single array of arguments.
     *
     * @private
     * @param {Array|Object} args The provided arguments.
     * @param {Array} partials The arguments to prepend to those provided.
     * @param {Array} holders The `partials` placeholder indexes.
     * @returns {Array} Returns the new array of composed arguments.
     */
    function composeArgs(args, partials, holders) {
      var holdersLength = holders.length,
          argsIndex = -1,
          argsLength = nativeMax(args.length - holdersLength, 0),
          leftIndex = -1,
          leftLength = partials.length,
          result = Array(argsLength + leftLength);

      while (++leftIndex < leftLength) {
        result[leftIndex] = partials[leftIndex];
      }
      while (++argsIndex < holdersLength) {
        result[holders[argsIndex]] = args[argsIndex];
      }
      while (argsLength--) {
        result[leftIndex++] = args[argsIndex++];
      }
      return result;
    }

    /**
     * This function is like `composeArgs` except that the arguments composition
     * is tailored for `_.partialRight`.
     *
     * @private
     * @param {Array|Object} args The provided arguments.
     * @param {Array} partials The arguments to append to those provided.
     * @param {Array} holders The `partials` placeholder indexes.
     * @returns {Array} Returns the new array of composed arguments.
     */
    function composeArgsRight(args, partials, holders) {
      var holdersIndex = -1,
          holdersLength = holders.length,
          argsIndex = -1,
          argsLength = nativeMax(args.length - holdersLength, 0),
          rightIndex = -1,
          rightLength = partials.length,
          result = Array(argsLength + rightLength);

      while (++argsIndex < argsLength) {
        result[argsIndex] = args[argsIndex];
      }
      var offset = argsIndex;
      while (++rightIndex < rightLength) {
        result[offset + rightIndex] = partials[rightIndex];
      }
      while (++holdersIndex < holdersLength) {
        result[offset + holders[holdersIndex]] = args[argsIndex++];
      }
      return result;
    }

    /**
     * Creates a function that aggregates a collection, creating an accumulator
     * object composed from the results of running each element in the collection
     * through an iteratee.
     *
     * **Note:** This function is used to create `_.countBy`, `_.groupBy`, `_.indexBy`,
     * and `_.partition`.
     *
     * @private
     * @param {Function} setter The function to set keys and values of the accumulator object.
     * @param {Function} [initializer] The function to initialize the accumulator object.
     * @returns {Function} Returns the new aggregator function.
     */
    function createAggregator(setter, initializer) {
      return function(collection, iteratee, thisArg) {
        var result = initializer ? initializer() : {};
        iteratee = getCallback(iteratee, thisArg, 3);

        if (isArray(collection)) {
          var index = -1,
              length = collection.length;

          while (++index < length) {
            var value = collection[index];
            setter(result, value, iteratee(value, index, collection), collection);
          }
        } else {
          baseEach(collection, function(value, key, collection) {
            setter(result, value, iteratee(value, key, collection), collection);
          });
        }
        return result;
      };
    }

    /**
     * Creates a function that assigns properties of source object(s) to a given
     * destination object.
     *
     * **Note:** This function is used to create `_.assign`, `_.defaults`, and `_.merge`.
     *
     * @private
     * @param {Function} assigner The function to assign values.
     * @returns {Function} Returns the new assigner function.
     */
    function createAssigner(assigner) {
      return restParam(function(object, sources) {
        var index = -1,
            length = object == null ? 0 : sources.length,
            customizer = length > 2 ? sources[length - 2] : undefined,
            guard = length > 2 ? sources[2] : undefined,
            thisArg = length > 1 ? sources[length - 1] : undefined;

        if (typeof customizer == 'function') {
          customizer = bindCallback(customizer, thisArg, 5);
          length -= 2;
        } else {
          customizer = typeof thisArg == 'function' ? thisArg : undefined;
          length -= (customizer ? 1 : 0);
        }
        if (guard && isIterateeCall(sources[0], sources[1], guard)) {
          customizer = length < 3 ? undefined : customizer;
          length = 1;
        }
        while (++index < length) {
          var source = sources[index];
          if (source) {
            assigner(object, source, customizer);
          }
        }
        return object;
      });
    }

    /**
     * Creates a `baseEach` or `baseEachRight` function.
     *
     * @private
     * @param {Function} eachFunc The function to iterate over a collection.
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Function} Returns the new base function.
     */
    function createBaseEach(eachFunc, fromRight) {
      return function(collection, iteratee) {
        var length = collection ? getLength(collection) : 0;
        if (!isLength(length)) {
          return eachFunc(collection, iteratee);
        }
        var index = fromRight ? length : -1,
            iterable = toObject(collection);

        while ((fromRight ? index-- : ++index < length)) {
          if (iteratee(iterable[index], index, iterable) === false) {
            break;
          }
        }
        return collection;
      };
    }

    /**
     * Creates a base function for `_.forIn` or `_.forInRight`.
     *
     * @private
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Function} Returns the new base function.
     */
    function createBaseFor(fromRight) {
      return function(object, iteratee, keysFunc) {
        var iterable = toObject(object),
            props = keysFunc(object),
            length = props.length,
            index = fromRight ? length : -1;

        while ((fromRight ? index-- : ++index < length)) {
          var key = props[index];
          if (iteratee(iterable[key], key, iterable) === false) {
            break;
          }
        }
        return object;
      };
    }

    /**
     * Creates a function that wraps `func` and invokes it with the `this`
     * binding of `thisArg`.
     *
     * @private
     * @param {Function} func The function to bind.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @returns {Function} Returns the new bound function.
     */
    function createBindWrapper(func, thisArg) {
      var Ctor = createCtorWrapper(func);

      function wrapper() {
        var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
        return fn.apply(thisArg, arguments);
      }
      return wrapper;
    }

    /**
     * Creates a `Set` cache object to optimize linear searches of large arrays.
     *
     * @private
     * @param {Array} [values] The values to cache.
     * @returns {null|Object} Returns the new cache object if `Set` is supported, else `null`.
     */
    var createCache = !(nativeCreate && Set) ? constant(null) : function(values) {
      return new SetCache(values);
    };

    /**
     * Creates a function that produces compound words out of the words in a
     * given string.
     *
     * @private
     * @param {Function} callback The function to combine each word.
     * @returns {Function} Returns the new compounder function.
     */
    function createCompounder(callback) {
      return function(string) {
        var index = -1,
            array = words(deburr(string)),
            length = array.length,
            result = '';

        while (++index < length) {
          result = callback(result, array[index], index);
        }
        return result;
      };
    }

    /**
     * Creates a function that produces an instance of `Ctor` regardless of
     * whether it was invoked as part of a `new` expression or by `call` or `apply`.
     *
     * @private
     * @param {Function} Ctor The constructor to wrap.
     * @returns {Function} Returns the new wrapped function.
     */
    function createCtorWrapper(Ctor) {
      return function() {
        // Use a `switch` statement to work with class constructors.
        // See https://people.mozilla.org/~jorendorff/es6-draft.html#sec-ecmascript-function-objects-call-thisargument-argumentslist
        // for more details.
        var args = arguments;
        switch (args.length) {
          case 0: return new Ctor;
          case 1: return new Ctor(args[0]);
          case 2: return new Ctor(args[0], args[1]);
          case 3: return new Ctor(args[0], args[1], args[2]);
          case 4: return new Ctor(args[0], args[1], args[2], args[3]);
          case 5: return new Ctor(args[0], args[1], args[2], args[3], args[4]);
        }
        var thisBinding = baseCreate(Ctor.prototype),
            result = Ctor.apply(thisBinding, args);

        // Mimic the constructor's `return` behavior.
        // See https://es5.github.io/#x13.2.2 for more details.
        return isObject(result) ? result : thisBinding;
      };
    }

    /**
     * Creates a `_.curry` or `_.curryRight` function.
     *
     * @private
     * @param {boolean} flag The curry bit flag.
     * @returns {Function} Returns the new curry function.
     */
    function createCurry(flag) {
      function curryFunc(func, arity, guard) {
        if (guard && isIterateeCall(func, arity, guard)) {
          arity = null;
        }
        var result = createWrapper(func, flag, null, null, null, null, null, arity);
        result.placeholder = curryFunc.placeholder;
        return result;
      }
      return curryFunc;
    }

    /**
     * Creates a `_.max` or `_.min` function.
     *
     * @private
     * @param {Function} comparator The function used to compare values.
     * @param {*} exValue The initial extremum value.
     * @returns {Function} Returns the new extremum function.
     */
    function createExtremum(comparator, exValue) {
      return function(collection, iteratee, thisArg) {
        if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
          iteratee = null;
        }
        iteratee = getCallback(iteratee, thisArg, 3);
        if (iteratee.length == 1) {
          collection = toIterable(collection);
          var result = arrayExtremum(collection, iteratee, comparator, exValue);
          if (!(collection.length && result === exValue)) {
            return result;
          }
        }
        return baseExtremum(collection, iteratee, comparator, exValue);
      };
    }

    /**
     * Creates a `_.find` or `_.findLast` function.
     *
     * @private
     * @param {Function} eachFunc The function to iterate over a collection.
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Function} Returns the new find function.
     */
    function createFind(eachFunc, fromRight) {
      return function(collection, predicate, thisArg) {
        predicate = getCallback(predicate, thisArg, 3);
        if (isArray(collection)) {
          var index = baseFindIndex(collection, predicate, fromRight);
          return index > -1 ? collection[index] : undefined;
        }
        return baseFind(collection, predicate, eachFunc);
      };
    }

    /**
     * Creates a `_.findIndex` or `_.findLastIndex` function.
     *
     * @private
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Function} Returns the new find function.
     */
    function createFindIndex(fromRight) {
      return function(array, predicate, thisArg) {
        if (!(array && array.length)) {
          return -1;
        }
        predicate = getCallback(predicate, thisArg, 3);
        return baseFindIndex(array, predicate, fromRight);
      };
    }

    /**
     * Creates a `_.findKey` or `_.findLastKey` function.
     *
     * @private
     * @param {Function} objectFunc The function to iterate over an object.
     * @returns {Function} Returns the new find function.
     */
    function createFindKey(objectFunc) {
      return function(object, predicate, thisArg) {
        predicate = getCallback(predicate, thisArg, 3);
        return baseFind(object, predicate, objectFunc, true);
      };
    }

    /**
     * Creates a `_.flow` or `_.flowRight` function.
     *
     * @private
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Function} Returns the new flow function.
     */
    function createFlow(fromRight) {
      return function() {
        var wrapper,
            length = arguments.length,
            index = fromRight ? length : -1,
            leftIndex = 0,
            funcs = Array(length);

        while ((fromRight ? index-- : ++index < length)) {
          var func = funcs[leftIndex++] = arguments[index];
          if (typeof func != 'function') {
            throw new TypeError(FUNC_ERROR_TEXT);
          }
          if (!wrapper && LodashWrapper.prototype.thru && getFuncName(func) == 'wrapper') {
            wrapper = new LodashWrapper([]);
          }
        }
        index = wrapper ? -1 : length;
        while (++index < length) {
          func = funcs[index];

          var funcName = getFuncName(func),
              data = funcName == 'wrapper' ? getData(func) : null;

          if (data && isLaziable(data[0]) && data[1] == (ARY_FLAG | CURRY_FLAG | PARTIAL_FLAG | REARG_FLAG) && !data[4].length && data[9] == 1) {
            wrapper = wrapper[getFuncName(data[0])].apply(wrapper, data[3]);
          } else {
            wrapper = (func.length == 1 && isLaziable(func)) ? wrapper[funcName]() : wrapper.thru(func);
          }
        }
        return function() {
          var args = arguments;
          if (wrapper && args.length == 1 && isArray(args[0])) {
            return wrapper.plant(args[0]).value();
          }
          var index = 0,
              result = length ? funcs[index].apply(this, args) : args[0];

          while (++index < length) {
            result = funcs[index].call(this, result);
          }
          return result;
        };
      };
    }

    /**
     * Creates a function for `_.forEach` or `_.forEachRight`.
     *
     * @private
     * @param {Function} arrayFunc The function to iterate over an array.
     * @param {Function} eachFunc The function to iterate over a collection.
     * @returns {Function} Returns the new each function.
     */
    function createForEach(arrayFunc, eachFunc) {
      return function(collection, iteratee, thisArg) {
        return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
          ? arrayFunc(collection, iteratee)
          : eachFunc(collection, bindCallback(iteratee, thisArg, 3));
      };
    }

    /**
     * Creates a function for `_.forIn` or `_.forInRight`.
     *
     * @private
     * @param {Function} objectFunc The function to iterate over an object.
     * @returns {Function} Returns the new each function.
     */
    function createForIn(objectFunc) {
      return function(object, iteratee, thisArg) {
        if (typeof iteratee != 'function' || thisArg !== undefined) {
          iteratee = bindCallback(iteratee, thisArg, 3);
        }
        return objectFunc(object, iteratee, keysIn);
      };
    }

    /**
     * Creates a function for `_.forOwn` or `_.forOwnRight`.
     *
     * @private
     * @param {Function} objectFunc The function to iterate over an object.
     * @returns {Function} Returns the new each function.
     */
    function createForOwn(objectFunc) {
      return function(object, iteratee, thisArg) {
        if (typeof iteratee != 'function' || thisArg !== undefined) {
          iteratee = bindCallback(iteratee, thisArg, 3);
        }
        return objectFunc(object, iteratee);
      };
    }

    /**
     * Creates a function for `_.mapKeys` or `_.mapValues`.
     *
     * @private
     * @param {boolean} [isMapKeys] Specify mapping keys instead of values.
     * @returns {Function} Returns the new map function.
     */
    function createObjectMapper(isMapKeys) {
      return function(object, iteratee, thisArg) {
        var result = {};
        iteratee = getCallback(iteratee, thisArg, 3);

        baseForOwn(object, function(value, key, object) {
          var mapped = iteratee(value, key, object);
          key = isMapKeys ? mapped : key;
          value = isMapKeys ? value : mapped;
          result[key] = value;
        });
        return result;
      };
    }

    /**
     * Creates a function for `_.padLeft` or `_.padRight`.
     *
     * @private
     * @param {boolean} [fromRight] Specify padding from the right.
     * @returns {Function} Returns the new pad function.
     */
    function createPadDir(fromRight) {
      return function(string, length, chars) {
        string = baseToString(string);
        return (fromRight ? string : '') + createPadding(string, length, chars) + (fromRight ? '' : string);
      };
    }

    /**
     * Creates a `_.partial` or `_.partialRight` function.
     *
     * @private
     * @param {boolean} flag The partial bit flag.
     * @returns {Function} Returns the new partial function.
     */
    function createPartial(flag) {
      var partialFunc = restParam(function(func, partials) {
        var holders = replaceHolders(partials, partialFunc.placeholder);
        return createWrapper(func, flag, null, partials, holders);
      });
      return partialFunc;
    }

    /**
     * Creates a function for `_.reduce` or `_.reduceRight`.
     *
     * @private
     * @param {Function} arrayFunc The function to iterate over an array.
     * @param {Function} eachFunc The function to iterate over a collection.
     * @returns {Function} Returns the new each function.
     */
    function createReduce(arrayFunc, eachFunc) {
      return function(collection, iteratee, accumulator, thisArg) {
        var initFromArray = arguments.length < 3;
        return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
          ? arrayFunc(collection, iteratee, accumulator, initFromArray)
          : baseReduce(collection, getCallback(iteratee, thisArg, 4), accumulator, initFromArray, eachFunc);
      };
    }

    /**
     * Creates a function that wraps `func` and invokes it with optional `this`
     * binding of, partial application, and currying.
     *
     * @private
     * @param {Function|string} func The function or method name to reference.
     * @param {number} bitmask The bitmask of flags. See `createWrapper` for more details.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @param {Array} [partials] The arguments to prepend to those provided to the new function.
     * @param {Array} [holders] The `partials` placeholder indexes.
     * @param {Array} [partialsRight] The arguments to append to those provided to the new function.
     * @param {Array} [holdersRight] The `partialsRight` placeholder indexes.
     * @param {Array} [argPos] The argument positions of the new function.
     * @param {number} [ary] The arity cap of `func`.
     * @param {number} [arity] The arity of `func`.
     * @returns {Function} Returns the new wrapped function.
     */
    function createHybridWrapper(func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity) {
      var isAry = bitmask & ARY_FLAG,
          isBind = bitmask & BIND_FLAG,
          isBindKey = bitmask & BIND_KEY_FLAG,
          isCurry = bitmask & CURRY_FLAG,
          isCurryBound = bitmask & CURRY_BOUND_FLAG,
          isCurryRight = bitmask & CURRY_RIGHT_FLAG,
          Ctor = isBindKey ? null : createCtorWrapper(func);

      function wrapper() {
        // Avoid `arguments` object use disqualifying optimizations by
        // converting it to an array before providing it to other functions.
        var length = arguments.length,
            index = length,
            args = Array(length);

        while (index--) {
          args[index] = arguments[index];
        }
        if (partials) {
          args = composeArgs(args, partials, holders);
        }
        if (partialsRight) {
          args = composeArgsRight(args, partialsRight, holdersRight);
        }
        if (isCurry || isCurryRight) {
          var placeholder = wrapper.placeholder,
              argsHolders = replaceHolders(args, placeholder);

          length -= argsHolders.length;
          if (length < arity) {
            var newArgPos = argPos ? arrayCopy(argPos) : null,
                newArity = nativeMax(arity - length, 0),
                newsHolders = isCurry ? argsHolders : null,
                newHoldersRight = isCurry ? null : argsHolders,
                newPartials = isCurry ? args : null,
                newPartialsRight = isCurry ? null : args;

            bitmask |= (isCurry ? PARTIAL_FLAG : PARTIAL_RIGHT_FLAG);
            bitmask &= ~(isCurry ? PARTIAL_RIGHT_FLAG : PARTIAL_FLAG);

            if (!isCurryBound) {
              bitmask &= ~(BIND_FLAG | BIND_KEY_FLAG);
            }
            var newData = [func, bitmask, thisArg, newPartials, newsHolders, newPartialsRight, newHoldersRight, newArgPos, ary, newArity],
                result = createHybridWrapper.apply(undefined, newData);

            if (isLaziable(func)) {
              setData(result, newData);
            }
            result.placeholder = placeholder;
            return result;
          }
        }
        var thisBinding = isBind ? thisArg : this,
            fn = isBindKey ? thisBinding[func] : func;

        if (argPos) {
          args = reorder(args, argPos);
        }
        if (isAry && ary < args.length) {
          args.length = ary;
        }
        if (this && this !== root && this instanceof wrapper) {
          fn = Ctor || createCtorWrapper(func);
        }
        return fn.apply(thisBinding, args);
      }
      return wrapper;
    }

    /**
     * Creates the padding required for `string` based on the given `length`.
     * The `chars` string is truncated if the number of characters exceeds `length`.
     *
     * @private
     * @param {string} string The string to create padding for.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the pad for `string`.
     */
    function createPadding(string, length, chars) {
      var strLength = string.length;
      length = +length;

      if (strLength >= length || !nativeIsFinite(length)) {
        return '';
      }
      var padLength = length - strLength;
      chars = chars == null ? ' ' : (chars + '');
      return repeat(chars, ceil(padLength / chars.length)).slice(0, padLength);
    }

    /**
     * Creates a function that wraps `func` and invokes it with the optional `this`
     * binding of `thisArg` and the `partials` prepended to those provided to
     * the wrapper.
     *
     * @private
     * @param {Function} func The function to partially apply arguments to.
     * @param {number} bitmask The bitmask of flags. See `createWrapper` for more details.
     * @param {*} thisArg The `this` binding of `func`.
     * @param {Array} partials The arguments to prepend to those provided to the new function.
     * @returns {Function} Returns the new bound function.
     */
    function createPartialWrapper(func, bitmask, thisArg, partials) {
      var isBind = bitmask & BIND_FLAG,
          Ctor = createCtorWrapper(func);

      function wrapper() {
        // Avoid `arguments` object use disqualifying optimizations by
        // converting it to an array before providing it `func`.
        var argsIndex = -1,
            argsLength = arguments.length,
            leftIndex = -1,
            leftLength = partials.length,
            args = Array(argsLength + leftLength);

        while (++leftIndex < leftLength) {
          args[leftIndex] = partials[leftIndex];
        }
        while (argsLength--) {
          args[leftIndex++] = arguments[++argsIndex];
        }
        var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
        return fn.apply(isBind ? thisArg : this, args);
      }
      return wrapper;
    }

    /**
     * Creates a `_.sortedIndex` or `_.sortedLastIndex` function.
     *
     * @private
     * @param {boolean} [retHighest] Specify returning the highest qualified index.
     * @returns {Function} Returns the new index function.
     */
    function createSortedIndex(retHighest) {
      return function(array, value, iteratee, thisArg) {
        var callback = getCallback(iteratee);
        return (iteratee == null && callback === baseCallback)
          ? binaryIndex(array, value, retHighest)
          : binaryIndexBy(array, value, callback(iteratee, thisArg, 1), retHighest);
      };
    }

    /**
     * Creates a function that either curries or invokes `func` with optional
     * `this` binding and partially applied arguments.
     *
     * @private
     * @param {Function|string} func The function or method name to reference.
     * @param {number} bitmask The bitmask of flags.
     *  The bitmask may be composed of the following flags:
     *     1 - `_.bind`
     *     2 - `_.bindKey`
     *     4 - `_.curry` or `_.curryRight` of a bound function
     *     8 - `_.curry`
     *    16 - `_.curryRight`
     *    32 - `_.partial`
     *    64 - `_.partialRight`
     *   128 - `_.rearg`
     *   256 - `_.ary`
     * @param {*} [thisArg] The `this` binding of `func`.
     * @param {Array} [partials] The arguments to be partially applied.
     * @param {Array} [holders] The `partials` placeholder indexes.
     * @param {Array} [argPos] The argument positions of the new function.
     * @param {number} [ary] The arity cap of `func`.
     * @param {number} [arity] The arity of `func`.
     * @returns {Function} Returns the new wrapped function.
     */
    function createWrapper(func, bitmask, thisArg, partials, holders, argPos, ary, arity) {
      var isBindKey = bitmask & BIND_KEY_FLAG;
      if (!isBindKey && typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      var length = partials ? partials.length : 0;
      if (!length) {
        bitmask &= ~(PARTIAL_FLAG | PARTIAL_RIGHT_FLAG);
        partials = holders = null;
      }
      length -= (holders ? holders.length : 0);
      if (bitmask & PARTIAL_RIGHT_FLAG) {
        var partialsRight = partials,
            holdersRight = holders;

        partials = holders = null;
      }
      var data = isBindKey ? null : getData(func),
          newData = [func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity];

      if (data) {
        mergeData(newData, data);
        bitmask = newData[1];
        arity = newData[9];
      }
      newData[9] = arity == null
        ? (isBindKey ? 0 : func.length)
        : (nativeMax(arity - length, 0) || 0);

      if (bitmask == BIND_FLAG) {
        var result = createBindWrapper(newData[0], newData[2]);
      } else if ((bitmask == PARTIAL_FLAG || bitmask == (BIND_FLAG | PARTIAL_FLAG)) && !newData[4].length) {
        result = createPartialWrapper.apply(undefined, newData);
      } else {
        result = createHybridWrapper.apply(undefined, newData);
      }
      var setter = data ? baseSetData : setData;
      return setter(result, newData);
    }

    /**
     * A specialized version of `baseIsEqualDeep` for arrays with support for
     * partial deep comparisons.
     *
     * @private
     * @param {Array} array The array to compare.
     * @param {Array} other The other array to compare.
     * @param {Function} equalFunc The function to determine equivalents of values.
     * @param {Function} [customizer] The function to customize comparing arrays.
     * @param {boolean} [isLoose] Specify performing partial comparisons.
     * @param {Array} [stackA] Tracks traversed `value` objects.
     * @param {Array} [stackB] Tracks traversed `other` objects.
     * @returns {boolean} Returns `true` if the arrays are equivalent, else `false`.
     */
    function equalArrays(array, other, equalFunc, customizer, isLoose, stackA, stackB) {
      var index = -1,
          arrLength = array.length,
          othLength = other.length;

      if (arrLength != othLength && !(isLoose && othLength > arrLength)) {
        return false;
      }
      // Ignore non-index properties.
      while (++index < arrLength) {
        var arrValue = array[index],
            othValue = other[index],
            result = customizer ? customizer(isLoose ? othValue : arrValue, isLoose ? arrValue : othValue, index) : undefined;

        if (result !== undefined) {
          if (result) {
            continue;
          }
          return false;
        }
        // Recursively compare arrays (susceptible to call stack limits).
        if (isLoose) {
          if (!arraySome(other, function(othValue) {
                return arrValue === othValue || equalFunc(arrValue, othValue, customizer, isLoose, stackA, stackB);
              })) {
            return false;
          }
        } else if (!(arrValue === othValue || equalFunc(arrValue, othValue, customizer, isLoose, stackA, stackB))) {
          return false;
        }
      }
      return true;
    }

    /**
     * A specialized version of `baseIsEqualDeep` for comparing objects of
     * the same `toStringTag`.
     *
     * **Note:** This function only supports comparing values with tags of
     * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
     *
     * @private
     * @param {Object} value The object to compare.
     * @param {Object} other The other object to compare.
     * @param {string} tag The `toStringTag` of the objects to compare.
     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
     */
    function equalByTag(object, other, tag) {
      switch (tag) {
        case boolTag:
        case dateTag:
          // Coerce dates and booleans to numbers, dates to milliseconds and booleans
          // to `1` or `0` treating invalid dates coerced to `NaN` as not equal.
          return +object == +other;

        case errorTag:
          return object.name == other.name && object.message == other.message;

        case numberTag:
          // Treat `NaN` vs. `NaN` as equal.
          return (object != +object)
            ? other != +other
            : object == +other;

        case regexpTag:
        case stringTag:
          // Coerce regexes to strings and treat strings primitives and string
          // objects as equal. See https://es5.github.io/#x15.10.6.4 for more details.
          return object == (other + '');
      }
      return false;
    }

    /**
     * A specialized version of `baseIsEqualDeep` for objects with support for
     * partial deep comparisons.
     *
     * @private
     * @param {Object} object The object to compare.
     * @param {Object} other The other object to compare.
     * @param {Function} equalFunc The function to determine equivalents of values.
     * @param {Function} [customizer] The function to customize comparing values.
     * @param {boolean} [isLoose] Specify performing partial comparisons.
     * @param {Array} [stackA] Tracks traversed `value` objects.
     * @param {Array} [stackB] Tracks traversed `other` objects.
     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
     */
    function equalObjects(object, other, equalFunc, customizer, isLoose, stackA, stackB) {
      var objProps = keys(object),
          objLength = objProps.length,
          othProps = keys(other),
          othLength = othProps.length;

      if (objLength != othLength && !isLoose) {
        return false;
      }
      var index = objLength;
      while (index--) {
        var key = objProps[index];
        if (!(isLoose ? key in other : hasOwnProperty.call(other, key))) {
          return false;
        }
      }
      var skipCtor = isLoose;
      while (++index < objLength) {
        key = objProps[index];
        var objValue = object[key],
            othValue = other[key],
            result = customizer ? customizer(isLoose ? othValue : objValue, isLoose? objValue : othValue, key) : undefined;

        // Recursively compare objects (susceptible to call stack limits).
        if (!(result === undefined ? equalFunc(objValue, othValue, customizer, isLoose, stackA, stackB) : result)) {
          return false;
        }
        skipCtor || (skipCtor = key == 'constructor');
      }
      if (!skipCtor) {
        var objCtor = object.constructor,
            othCtor = other.constructor;

        // Non `Object` object instances with different constructors are not equal.
        if (objCtor != othCtor &&
            ('constructor' in object && 'constructor' in other) &&
            !(typeof objCtor == 'function' && objCtor instanceof objCtor &&
              typeof othCtor == 'function' && othCtor instanceof othCtor)) {
          return false;
        }
      }
      return true;
    }

    /**
     * Gets the appropriate "callback" function. If the `_.callback` method is
     * customized this function returns the custom method, otherwise it returns
     * the `baseCallback` function. If arguments are provided the chosen function
     * is invoked with them and its result is returned.
     *
     * @private
     * @returns {Function} Returns the chosen function or its result.
     */
    function getCallback(func, thisArg, argCount) {
      var result = lodash.callback || callback;
      result = result === callback ? baseCallback : result;
      return argCount ? result(func, thisArg, argCount) : result;
    }

    /**
     * Gets metadata for `func`.
     *
     * @private
     * @param {Function} func The function to query.
     * @returns {*} Returns the metadata for `func`.
     */
    var getData = !metaMap ? noop : function(func) {
      return metaMap.get(func);
    };

    /**
     * Gets the name of `func`.
     *
     * @private
     * @param {Function} func The function to query.
     * @returns {string} Returns the function name.
     */
    function getFuncName(func) {
      var result = func.name,
          array = realNames[result],
          length = array ? array.length : 0;

      while (length--) {
        var data = array[length],
            otherFunc = data.func;
        if (otherFunc == null || otherFunc == func) {
          return data.name;
        }
      }
      return result;
    }

    /**
     * Gets the appropriate "indexOf" function. If the `_.indexOf` method is
     * customized this function returns the custom method, otherwise it returns
     * the `baseIndexOf` function. If arguments are provided the chosen function
     * is invoked with them and its result is returned.
     *
     * @private
     * @returns {Function|number} Returns the chosen function or its result.
     */
    function getIndexOf(collection, target, fromIndex) {
      var result = lodash.indexOf || indexOf;
      result = result === indexOf ? baseIndexOf : result;
      return collection ? result(collection, target, fromIndex) : result;
    }

    /**
     * Gets the "length" property value of `object`.
     *
     * **Note:** This function is used to avoid a [JIT bug](https://bugs.webkit.org/show_bug.cgi?id=142792)
     * that affects Safari on at least iOS 8.1-8.3 ARM64.
     *
     * @private
     * @param {Object} object The object to query.
     * @returns {*} Returns the "length" value.
     */
    var getLength = baseProperty('length');

    /**
     * Gets the propery names, values, and compare flags of `object`.
     *
     * @private
     * @param {Object} object The object to query.
     * @returns {Array} Returns the match data of `object`.
     */
    function getMatchData(object) {
      var result = pairs(object),
          length = result.length;

      while (length--) {
        result[length][2] = isStrictComparable(result[length][1]);
      }
      return result;
    }

    /**
     * Gets the native function at `key` of `object`.
     *
     * @private
     * @param {Object} object The object to query.
     * @param {string} key The key of the method to get.
     * @returns {*} Returns the function if it's native, else `undefined`.
     */
    function getNative(object, key) {
      var value = object == null ? undefined : object[key];
      return isNative(value) ? value : undefined;
    }

    /**
     * Gets the view, applying any `transforms` to the `start` and `end` positions.
     *
     * @private
     * @param {number} start The start of the view.
     * @param {number} end The end of the view.
     * @param {Array} [transforms] The transformations to apply to the view.
     * @returns {Object} Returns an object containing the `start` and `end`
     *  positions of the view.
     */
    function getView(start, end, transforms) {
      var index = -1,
          length = transforms ? transforms.length : 0;

      while (++index < length) {
        var data = transforms[index],
            size = data.size;

        switch (data.type) {
          case 'drop':      start += size; break;
          case 'dropRight': end -= size; break;
          case 'take':      end = nativeMin(end, start + size); break;
          case 'takeRight': start = nativeMax(start, end - size); break;
        }
      }
      return { 'start': start, 'end': end };
    }

    /**
     * Initializes an array clone.
     *
     * @private
     * @param {Array} array The array to clone.
     * @returns {Array} Returns the initialized clone.
     */
    function initCloneArray(array) {
      var length = array.length,
          result = new array.constructor(length);

      // Add array properties assigned by `RegExp#exec`.
      if (length && typeof array[0] == 'string' && hasOwnProperty.call(array, 'index')) {
        result.index = array.index;
        result.input = array.input;
      }
      return result;
    }

    /**
     * Initializes an object clone.
     *
     * @private
     * @param {Object} object The object to clone.
     * @returns {Object} Returns the initialized clone.
     */
    function initCloneObject(object) {
      var Ctor = object.constructor;
      if (!(typeof Ctor == 'function' && Ctor instanceof Ctor)) {
        Ctor = Object;
      }
      return new Ctor;
    }

    /**
     * Initializes an object clone based on its `toStringTag`.
     *
     * **Note:** This function only supports cloning values with tags of
     * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
     *
     * @private
     * @param {Object} object The object to clone.
     * @param {string} tag The `toStringTag` of the object to clone.
     * @param {boolean} [isDeep] Specify a deep clone.
     * @returns {Object} Returns the initialized clone.
     */
    function initCloneByTag(object, tag, isDeep) {
      var Ctor = object.constructor;
      switch (tag) {
        case arrayBufferTag:
          return bufferClone(object);

        case boolTag:
        case dateTag:
          return new Ctor(+object);

        case float32Tag: case float64Tag:
        case int8Tag: case int16Tag: case int32Tag:
        case uint8Tag: case uint8ClampedTag: case uint16Tag: case uint32Tag:
          var buffer = object.buffer;
          return new Ctor(isDeep ? bufferClone(buffer) : buffer, object.byteOffset, object.length);

        case numberTag:
        case stringTag:
          return new Ctor(object);

        case regexpTag:
          var result = new Ctor(object.source, reFlags.exec(object));
          result.lastIndex = object.lastIndex;
      }
      return result;
    }

    /**
     * Invokes the method at `path` on `object`.
     *
     * @private
     * @param {Object} object The object to query.
     * @param {Array|string} path The path of the method to invoke.
     * @param {Array} args The arguments to invoke the method with.
     * @returns {*} Returns the result of the invoked method.
     */
    function invokePath(object, path, args) {
      if (object != null && !isKey(path, object)) {
        path = toPath(path);
        object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
        path = last(path);
      }
      var func = object == null ? object : object[path];
      return func == null ? undefined : func.apply(object, args);
    }

    /**
     * Checks if `value` is array-like.
     *
     * @private
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is array-like, else `false`.
     */
    function isArrayLike(value) {
      return value != null && isLength(getLength(value));
    }

    /**
     * Checks if `value` is a valid array-like index.
     *
     * @private
     * @param {*} value The value to check.
     * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
     * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
     */
    function isIndex(value, length) {
      value = (typeof value == 'number' || reIsUint.test(value)) ? +value : -1;
      length = length == null ? MAX_SAFE_INTEGER : length;
      return value > -1 && value % 1 == 0 && value < length;
    }

    /**
     * Checks if the provided arguments are from an iteratee call.
     *
     * @private
     * @param {*} value The potential iteratee value argument.
     * @param {*} index The potential iteratee index or key argument.
     * @param {*} object The potential iteratee object argument.
     * @returns {boolean} Returns `true` if the arguments are from an iteratee call, else `false`.
     */
    function isIterateeCall(value, index, object) {
      if (!isObject(object)) {
        return false;
      }
      var type = typeof index;
      if (type == 'number'
          ? (isArrayLike(object) && isIndex(index, object.length))
          : (type == 'string' && index in object)) {
        var other = object[index];
        return value === value ? (value === other) : (other !== other);
      }
      return false;
    }

    /**
     * Checks if `value` is a property name and not a property path.
     *
     * @private
     * @param {*} value The value to check.
     * @param {Object} [object] The object to query keys on.
     * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
     */
    function isKey(value, object) {
      var type = typeof value;
      if ((type == 'string' && reIsPlainProp.test(value)) || type == 'number') {
        return true;
      }
      if (isArray(value)) {
        return false;
      }
      var result = !reIsDeepProp.test(value);
      return result || (object != null && value in toObject(object));
    }

    /**
     * Checks if `func` has a lazy counterpart.
     *
     * @private
     * @param {Function} func The function to check.
     * @returns {boolean} Returns `true` if `func` has a lazy counterpart, else `false`.
     */
    function isLaziable(func) {
      var funcName = getFuncName(func);
      if (!(funcName in LazyWrapper.prototype)) {
        return false;
      }
      var other = lodash[funcName];
      if (func === other) {
        return true;
      }
      var data = getData(other);
      return !!data && func === data[0];
    }

    /**
     * Checks if `value` is a valid array-like length.
     *
     * **Note:** This function is based on [`ToLength`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-tolength).
     *
     * @private
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a valid length, else `false`.
     */
    function isLength(value) {
      return typeof value == 'number' && value > -1 && value % 1 == 0 && value <= MAX_SAFE_INTEGER;
    }

    /**
     * Checks if `value` is suitable for strict equality comparisons, i.e. `===`.
     *
     * @private
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` if suitable for strict
     *  equality comparisons, else `false`.
     */
    function isStrictComparable(value) {
      return value === value && !isObject(value);
    }

    /**
     * Merges the function metadata of `source` into `data`.
     *
     * Merging metadata reduces the number of wrappers required to invoke a function.
     * This is possible because methods like `_.bind`, `_.curry`, and `_.partial`
     * may be applied regardless of execution order. Methods like `_.ary` and `_.rearg`
     * augment function arguments, making the order in which they are executed important,
     * preventing the merging of metadata. However, we make an exception for a safe
     * common case where curried functions have `_.ary` and or `_.rearg` applied.
     *
     * @private
     * @param {Array} data The destination metadata.
     * @param {Array} source The source metadata.
     * @returns {Array} Returns `data`.
     */
    function mergeData(data, source) {
      var bitmask = data[1],
          srcBitmask = source[1],
          newBitmask = bitmask | srcBitmask,
          isCommon = newBitmask < ARY_FLAG;

      var isCombo =
        (srcBitmask == ARY_FLAG && bitmask == CURRY_FLAG) ||
        (srcBitmask == ARY_FLAG && bitmask == REARG_FLAG && data[7].length <= source[8]) ||
        (srcBitmask == (ARY_FLAG | REARG_FLAG) && bitmask == CURRY_FLAG);

      // Exit early if metadata can't be merged.
      if (!(isCommon || isCombo)) {
        return data;
      }
      // Use source `thisArg` if available.
      if (srcBitmask & BIND_FLAG) {
        data[2] = source[2];
        // Set when currying a bound function.
        newBitmask |= (bitmask & BIND_FLAG) ? 0 : CURRY_BOUND_FLAG;
      }
      // Compose partial arguments.
      var value = source[3];
      if (value) {
        var partials = data[3];
        data[3] = partials ? composeArgs(partials, value, source[4]) : arrayCopy(value);
        data[4] = partials ? replaceHolders(data[3], PLACEHOLDER) : arrayCopy(source[4]);
      }
      // Compose partial right arguments.
      value = source[5];
      if (value) {
        partials = data[5];
        data[5] = partials ? composeArgsRight(partials, value, source[6]) : arrayCopy(value);
        data[6] = partials ? replaceHolders(data[5], PLACEHOLDER) : arrayCopy(source[6]);
      }
      // Use source `argPos` if available.
      value = source[7];
      if (value) {
        data[7] = arrayCopy(value);
      }
      // Use source `ary` if it's smaller.
      if (srcBitmask & ARY_FLAG) {
        data[8] = data[8] == null ? source[8] : nativeMin(data[8], source[8]);
      }
      // Use source `arity` if one is not provided.
      if (data[9] == null) {
        data[9] = source[9];
      }
      // Use source `func` and merge bitmasks.
      data[0] = source[0];
      data[1] = newBitmask;

      return data;
    }

    /**
     * A specialized version of `_.pick` which picks `object` properties specified
     * by `props`.
     *
     * @private
     * @param {Object} object The source object.
     * @param {string[]} props The property names to pick.
     * @returns {Object} Returns the new object.
     */
    function pickByArray(object, props) {
      object = toObject(object);

      var index = -1,
          length = props.length,
          result = {};

      while (++index < length) {
        var key = props[index];
        if (key in object) {
          result[key] = object[key];
        }
      }
      return result;
    }

    /**
     * A specialized version of `_.pick` which picks `object` properties `predicate`
     * returns truthy for.
     *
     * @private
     * @param {Object} object The source object.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {Object} Returns the new object.
     */
    function pickByCallback(object, predicate) {
      var result = {};
      baseForIn(object, function(value, key, object) {
        if (predicate(value, key, object)) {
          result[key] = value;
        }
      });
      return result;
    }

    /**
     * Reorder `array` according to the specified indexes where the element at
     * the first index is assigned as the first element, the element at
     * the second index is assigned as the second element, and so on.
     *
     * @private
     * @param {Array} array The array to reorder.
     * @param {Array} indexes The arranged array indexes.
     * @returns {Array} Returns `array`.
     */
    function reorder(array, indexes) {
      var arrLength = array.length,
          length = nativeMin(indexes.length, arrLength),
          oldArray = arrayCopy(array);

      while (length--) {
        var index = indexes[length];
        array[length] = isIndex(index, arrLength) ? oldArray[index] : undefined;
      }
      return array;
    }

    /**
     * Sets metadata for `func`.
     *
     * **Note:** If this function becomes hot, i.e. is invoked a lot in a short
     * period of time, it will trip its breaker and transition to an identity function
     * to avoid garbage collection pauses in V8. See [V8 issue 2070](https://code.google.com/p/v8/issues/detail?id=2070)
     * for more details.
     *
     * @private
     * @param {Function} func The function to associate metadata with.
     * @param {*} data The metadata.
     * @returns {Function} Returns `func`.
     */
    var setData = (function() {
      var count = 0,
          lastCalled = 0;

      return function(key, value) {
        var stamp = now(),
            remaining = HOT_SPAN - (stamp - lastCalled);

        lastCalled = stamp;
        if (remaining > 0) {
          if (++count >= HOT_COUNT) {
            return key;
          }
        } else {
          count = 0;
        }
        return baseSetData(key, value);
      };
    }());

    /**
     * A fallback implementation of `_.isPlainObject` which checks if `value`
     * is an object created by the `Object` constructor or has a `[[Prototype]]`
     * of `null`.
     *
     * @private
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
     */
    function shimIsPlainObject(value) {
      var Ctor,
          support = lodash.support;

      // Exit early for non `Object` objects.
      if (!(isObjectLike(value) && objToString.call(value) == objectTag) ||
          (!hasOwnProperty.call(value, 'constructor') &&
            (Ctor = value.constructor, typeof Ctor == 'function' && !(Ctor instanceof Ctor)))) {
        return false;
      }
      // IE < 9 iterates inherited properties before own properties. If the first
      // iterated property is an object's own property then there are no inherited
      // enumerable properties.
      var result;
      // In most environments an object's own properties are iterated before
      // its inherited properties. If the last iterated property is an object's
      // own property then there are no inherited enumerable properties.
      baseForIn(value, function(subValue, key) {
        result = key;
      });
      return result === undefined || hasOwnProperty.call(value, result);
    }

    /**
     * A fallback implementation of `Object.keys` which creates an array of the
     * own enumerable property names of `object`.
     *
     * @private
     * @param {Object} object The object to query.
     * @returns {Array} Returns the array of property names.
     */
    function shimKeys(object) {
      var props = keysIn(object),
          propsLength = props.length,
          length = propsLength && object.length;

      var allowIndexes = !!length && isLength(length) &&
        (isArray(object) || isArguments(object));

      var index = -1,
          result = [];

      while (++index < propsLength) {
        var key = props[index];
        if ((allowIndexes && isIndex(key, length)) || hasOwnProperty.call(object, key)) {
          result.push(key);
        }
      }
      return result;
    }

    /**
     * Converts `value` to an array-like object if it's not one.
     *
     * @private
     * @param {*} value The value to process.
     * @returns {Array|Object} Returns the array-like object.
     */
    function toIterable(value) {
      if (value == null) {
        return [];
      }
      if (!isArrayLike(value)) {
        return values(value);
      }
      return isObject(value) ? value : Object(value);
    }

    /**
     * Converts `value` to an object if it's not one.
     *
     * @private
     * @param {*} value The value to process.
     * @returns {Object} Returns the object.
     */
    function toObject(value) {
      return isObject(value) ? value : Object(value);
    }

    /**
     * Converts `value` to property path array if it's not one.
     *
     * @private
     * @param {*} value The value to process.
     * @returns {Array} Returns the property path array.
     */
    function toPath(value) {
      if (isArray(value)) {
        return value;
      }
      var result = [];
      baseToString(value).replace(rePropName, function(match, number, quote, string) {
        result.push(quote ? string.replace(reEscapeChar, '$1') : (number || match));
      });
      return result;
    }

    /**
     * Creates a clone of `wrapper`.
     *
     * @private
     * @param {Object} wrapper The wrapper to clone.
     * @returns {Object} Returns the cloned wrapper.
     */
    function wrapperClone(wrapper) {
      return wrapper instanceof LazyWrapper
        ? wrapper.clone()
        : new LodashWrapper(wrapper.__wrapped__, wrapper.__chain__, arrayCopy(wrapper.__actions__));
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates an array of elements split into groups the length of `size`.
     * If `collection` can't be split evenly, the final chunk will be the remaining
     * elements.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to process.
     * @param {number} [size=1] The length of each chunk.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the new array containing chunks.
     * @example
     *
     * _.chunk(['a', 'b', 'c', 'd'], 2);
     * // => [['a', 'b'], ['c', 'd']]
     *
     * _.chunk(['a', 'b', 'c', 'd'], 3);
     * // => [['a', 'b', 'c'], ['d']]
     */
    function chunk(array, size, guard) {
      if (guard ? isIterateeCall(array, size, guard) : size == null) {
        size = 1;
      } else {
        size = nativeMax(+size || 1, 1);
      }
      var index = 0,
          length = array ? array.length : 0,
          resIndex = -1,
          result = Array(ceil(length / size));

      while (index < length) {
        result[++resIndex] = baseSlice(array, index, (index += size));
      }
      return result;
    }

    /**
     * Creates an array with all falsey values removed. The values `false`, `null`,
     * `0`, `""`, `undefined`, and `NaN` are falsey.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to compact.
     * @returns {Array} Returns the new array of filtered values.
     * @example
     *
     * _.compact([0, 1, false, 2, '', 3]);
     * // => [1, 2, 3]
     */
    function compact(array) {
      var index = -1,
          length = array ? array.length : 0,
          resIndex = -1,
          result = [];

      while (++index < length) {
        var value = array[index];
        if (value) {
          result[++resIndex] = value;
        }
      }
      return result;
    }

    /**
     * Creates an array of unique `array` values not included in the other
     * provided arrays using [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for equality comparisons.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to inspect.
     * @param {...Array} [values] The arrays of values to exclude.
     * @returns {Array} Returns the new array of filtered values.
     * @example
     *
     * _.difference([1, 2, 3], [4, 2]);
     * // => [1, 3]
     */
    var difference = restParam(function(array, values) {
      return isArrayLike(array)
        ? baseDifference(array, baseFlatten(values, false, true))
        : [];
    });

    /**
     * Creates a slice of `array` with `n` elements dropped from the beginning.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to drop.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.drop([1, 2, 3]);
     * // => [2, 3]
     *
     * _.drop([1, 2, 3], 2);
     * // => [3]
     *
     * _.drop([1, 2, 3], 5);
     * // => []
     *
     * _.drop([1, 2, 3], 0);
     * // => [1, 2, 3]
     */
    function drop(array, n, guard) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (guard ? isIterateeCall(array, n, guard) : n == null) {
        n = 1;
      }
      return baseSlice(array, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` with `n` elements dropped from the end.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to drop.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.dropRight([1, 2, 3]);
     * // => [1, 2]
     *
     * _.dropRight([1, 2, 3], 2);
     * // => [1]
     *
     * _.dropRight([1, 2, 3], 5);
     * // => []
     *
     * _.dropRight([1, 2, 3], 0);
     * // => [1, 2, 3]
     */
    function dropRight(array, n, guard) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (guard ? isIterateeCall(array, n, guard) : n == null) {
        n = 1;
      }
      n = length - (+n || 0);
      return baseSlice(array, 0, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` excluding elements dropped from the end.
     * Elements are dropped until `predicate` returns falsey. The predicate is
     * bound to `thisArg` and invoked with three arguments: (value, index, array).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that match the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.dropRightWhile([1, 2, 3], function(n) {
     *   return n > 1;
     * });
     * // => [1]
     *
     * var users = [
     *   { 'user': 'barney',  'active': true },
     *   { 'user': 'fred',    'active': false },
     *   { 'user': 'pebbles', 'active': false }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.dropRightWhile(users, { 'user': 'pebbles', 'active': false }), 'user');
     * // => ['barney', 'fred']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.dropRightWhile(users, 'active', false), 'user');
     * // => ['barney']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.dropRightWhile(users, 'active'), 'user');
     * // => ['barney', 'fred', 'pebbles']
     */
    function dropRightWhile(array, predicate, thisArg) {
      return (array && array.length)
        ? baseWhile(array, getCallback(predicate, thisArg, 3), true, true)
        : [];
    }

    /**
     * Creates a slice of `array` excluding elements dropped from the beginning.
     * Elements are dropped until `predicate` returns falsey. The predicate is
     * bound to `thisArg` and invoked with three arguments: (value, index, array).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.dropWhile([1, 2, 3], function(n) {
     *   return n < 3;
     * });
     * // => [3]
     *
     * var users = [
     *   { 'user': 'barney',  'active': false },
     *   { 'user': 'fred',    'active': false },
     *   { 'user': 'pebbles', 'active': true }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.dropWhile(users, { 'user': 'barney', 'active': false }), 'user');
     * // => ['fred', 'pebbles']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.dropWhile(users, 'active', false), 'user');
     * // => ['pebbles']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.dropWhile(users, 'active'), 'user');
     * // => ['barney', 'fred', 'pebbles']
     */
    function dropWhile(array, predicate, thisArg) {
      return (array && array.length)
        ? baseWhile(array, getCallback(predicate, thisArg, 3), true)
        : [];
    }

    /**
     * Fills elements of `array` with `value` from `start` up to, but not
     * including, `end`.
     *
     * **Note:** This method mutates `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to fill.
     * @param {*} value The value to fill `array` with.
     * @param {number} [start=0] The start position.
     * @param {number} [end=array.length] The end position.
     * @returns {Array} Returns `array`.
     * @example
     *
     * var array = [1, 2, 3];
     *
     * _.fill(array, 'a');
     * console.log(array);
     * // => ['a', 'a', 'a']
     *
     * _.fill(Array(3), 2);
     * // => [2, 2, 2]
     *
     * _.fill([4, 6, 8], '*', 1, 2);
     * // => [4, '*', 8]
     */
    function fill(array, value, start, end) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (start && typeof start != 'number' && isIterateeCall(array, value, start)) {
        start = 0;
        end = length;
      }
      return baseFill(array, value, start, end);
    }

    /**
     * This method is like `_.find` except that it returns the index of the first
     * element `predicate` returns truthy for instead of the element itself.
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {number} Returns the index of the found element, else `-1`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'active': false },
     *   { 'user': 'fred',    'active': false },
     *   { 'user': 'pebbles', 'active': true }
     * ];
     *
     * _.findIndex(users, function(chr) {
     *   return chr.user == 'barney';
     * });
     * // => 0
     *
     * // using the `_.matches` callback shorthand
     * _.findIndex(users, { 'user': 'fred', 'active': false });
     * // => 1
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.findIndex(users, 'active', false);
     * // => 0
     *
     * // using the `_.property` callback shorthand
     * _.findIndex(users, 'active');
     * // => 2
     */
    var findIndex = createFindIndex();

    /**
     * This method is like `_.findIndex` except that it iterates over elements
     * of `collection` from right to left.
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {number} Returns the index of the found element, else `-1`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'active': true },
     *   { 'user': 'fred',    'active': false },
     *   { 'user': 'pebbles', 'active': false }
     * ];
     *
     * _.findLastIndex(users, function(chr) {
     *   return chr.user == 'pebbles';
     * });
     * // => 2
     *
     * // using the `_.matches` callback shorthand
     * _.findLastIndex(users, { 'user': 'barney', 'active': true });
     * // => 0
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.findLastIndex(users, 'active', false);
     * // => 2
     *
     * // using the `_.property` callback shorthand
     * _.findLastIndex(users, 'active');
     * // => 0
     */
    var findLastIndex = createFindIndex(true);

    /**
     * Gets the first element of `array`.
     *
     * @static
     * @memberOf _
     * @alias head
     * @category Array
     * @param {Array} array The array to query.
     * @returns {*} Returns the first element of `array`.
     * @example
     *
     * _.first([1, 2, 3]);
     * // => 1
     *
     * _.first([]);
     * // => undefined
     */
    function first(array) {
      return array ? array[0] : undefined;
    }

    /**
     * Flattens a nested array. If `isDeep` is `true` the array is recursively
     * flattened, otherwise it is only flattened a single level.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to flatten.
     * @param {boolean} [isDeep] Specify a deep flatten.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the new flattened array.
     * @example
     *
     * _.flatten([1, [2, 3, [4]]]);
     * // => [1, 2, 3, [4]]
     *
     * // using `isDeep`
     * _.flatten([1, [2, 3, [4]]], true);
     * // => [1, 2, 3, 4]
     */
    function flatten(array, isDeep, guard) {
      var length = array ? array.length : 0;
      if (guard && isIterateeCall(array, isDeep, guard)) {
        isDeep = false;
      }
      return length ? baseFlatten(array, isDeep) : [];
    }

    /**
     * Recursively flattens a nested array.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to recursively flatten.
     * @returns {Array} Returns the new flattened array.
     * @example
     *
     * _.flattenDeep([1, [2, 3, [4]]]);
     * // => [1, 2, 3, 4]
     */
    function flattenDeep(array) {
      var length = array ? array.length : 0;
      return length ? baseFlatten(array, true) : [];
    }

    /**
     * Gets the index at which the first occurrence of `value` is found in `array`
     * using [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for equality comparisons. If `fromIndex` is negative, it is used as the offset
     * from the end of `array`. If `array` is sorted providing `true` for `fromIndex`
     * performs a faster binary search.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {*} value The value to search for.
     * @param {boolean|number} [fromIndex=0] The index to search from or `true`
     *  to perform a binary search on a sorted array.
     * @returns {number} Returns the index of the matched value, else `-1`.
     * @example
     *
     * _.indexOf([1, 2, 1, 2], 2);
     * // => 1
     *
     * // using `fromIndex`
     * _.indexOf([1, 2, 1, 2], 2, 2);
     * // => 3
     *
     * // performing a binary search
     * _.indexOf([1, 1, 2, 2], 2, true);
     * // => 2
     */
    function indexOf(array, value, fromIndex) {
      var length = array ? array.length : 0;
      if (!length) {
        return -1;
      }
      if (typeof fromIndex == 'number') {
        fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : fromIndex;
      } else if (fromIndex) {
        var index = binaryIndex(array, value),
            other = array[index];

        if (value === value ? (value === other) : (other !== other)) {
          return index;
        }
        return -1;
      }
      return baseIndexOf(array, value, fromIndex || 0);
    }

    /**
     * Gets all but the last element of `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.initial([1, 2, 3]);
     * // => [1, 2]
     */
    function initial(array) {
      return dropRight(array, 1);
    }

    /**
     * Creates an array of unique values that are included in all of the provided
     * arrays using [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for equality comparisons.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to inspect.
     * @returns {Array} Returns the new array of shared values.
     * @example
     * _.intersection([1, 2], [4, 2], [2, 1]);
     * // => [2]
     */
    var intersection = restParam(function(arrays) {
      var othLength = arrays.length,
          othIndex = othLength,
          caches = Array(length),
          indexOf = getIndexOf(),
          isCommon = indexOf == baseIndexOf,
          result = [];

      while (othIndex--) {
        var value = arrays[othIndex] = isArrayLike(value = arrays[othIndex]) ? value : [];
        caches[othIndex] = (isCommon && value.length >= 120) ? createCache(othIndex && value) : null;
      }
      var array = arrays[0],
          index = -1,
          length = array ? array.length : 0,
          seen = caches[0];

      outer:
      while (++index < length) {
        value = array[index];
        if ((seen ? cacheIndexOf(seen, value) : indexOf(result, value, 0)) < 0) {
          var othIndex = othLength;
          while (--othIndex) {
            var cache = caches[othIndex];
            if ((cache ? cacheIndexOf(cache, value) : indexOf(arrays[othIndex], value, 0)) < 0) {
              continue outer;
            }
          }
          if (seen) {
            seen.push(value);
          }
          result.push(value);
        }
      }
      return result;
    });

    /**
     * Gets the last element of `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @returns {*} Returns the last element of `array`.
     * @example
     *
     * _.last([1, 2, 3]);
     * // => 3
     */
    function last(array) {
      var length = array ? array.length : 0;
      return length ? array[length - 1] : undefined;
    }

    /**
     * This method is like `_.indexOf` except that it iterates over elements of
     * `array` from right to left.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {*} value The value to search for.
     * @param {boolean|number} [fromIndex=array.length-1] The index to search from
     *  or `true` to perform a binary search on a sorted array.
     * @returns {number} Returns the index of the matched value, else `-1`.
     * @example
     *
     * _.lastIndexOf([1, 2, 1, 2], 2);
     * // => 3
     *
     * // using `fromIndex`
     * _.lastIndexOf([1, 2, 1, 2], 2, 2);
     * // => 1
     *
     * // performing a binary search
     * _.lastIndexOf([1, 1, 2, 2], 2, true);
     * // => 3
     */
    function lastIndexOf(array, value, fromIndex) {
      var length = array ? array.length : 0;
      if (!length) {
        return -1;
      }
      var index = length;
      if (typeof fromIndex == 'number') {
        index = (fromIndex < 0 ? nativeMax(length + fromIndex, 0) : nativeMin(fromIndex || 0, length - 1)) + 1;
      } else if (fromIndex) {
        index = binaryIndex(array, value, true) - 1;
        var other = array[index];
        if (value === value ? (value === other) : (other !== other)) {
          return index;
        }
        return -1;
      }
      if (value !== value) {
        return indexOfNaN(array, index, true);
      }
      while (index--) {
        if (array[index] === value) {
          return index;
        }
      }
      return -1;
    }

    /**
     * Removes all provided values from `array` using
     * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for equality comparisons.
     *
     * **Note:** Unlike `_.without`, this method mutates `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to modify.
     * @param {...*} [values] The values to remove.
     * @returns {Array} Returns `array`.
     * @example
     *
     * var array = [1, 2, 3, 1, 2, 3];
     *
     * _.pull(array, 2, 3);
     * console.log(array);
     * // => [1, 1]
     */
    function pull() {
      var args = arguments,
          array = args[0];

      if (!(array && array.length)) {
        return array;
      }
      var index = 0,
          indexOf = getIndexOf(),
          length = args.length;

      while (++index < length) {
        var fromIndex = 0,
            value = args[index];

        while ((fromIndex = indexOf(array, value, fromIndex)) > -1) {
          splice.call(array, fromIndex, 1);
        }
      }
      return array;
    }

    /**
     * Removes elements from `array` corresponding to the given indexes and returns
     * an array of the removed elements. Indexes may be specified as an array of
     * indexes or as individual arguments.
     *
     * **Note:** Unlike `_.at`, this method mutates `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to modify.
     * @param {...(number|number[])} [indexes] The indexes of elements to remove,
     *  specified as individual indexes or arrays of indexes.
     * @returns {Array} Returns the new array of removed elements.
     * @example
     *
     * var array = [5, 10, 15, 20];
     * var evens = _.pullAt(array, 1, 3);
     *
     * console.log(array);
     * // => [5, 15]
     *
     * console.log(evens);
     * // => [10, 20]
     */
    var pullAt = restParam(function(array, indexes) {
      indexes = baseFlatten(indexes);

      var result = baseAt(array, indexes);
      basePullAt(array, indexes.sort(baseCompareAscending));
      return result;
    });

    /**
     * Removes all elements from `array` that `predicate` returns truthy for
     * and returns an array of the removed elements. The predicate is bound to
     * `thisArg` and invoked with three arguments: (value, index, array).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * **Note:** Unlike `_.filter`, this method mutates `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to modify.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the new array of removed elements.
     * @example
     *
     * var array = [1, 2, 3, 4];
     * var evens = _.remove(array, function(n) {
     *   return n % 2 == 0;
     * });
     *
     * console.log(array);
     * // => [1, 3]
     *
     * console.log(evens);
     * // => [2, 4]
     */
    function remove(array, predicate, thisArg) {
      var result = [];
      if (!(array && array.length)) {
        return result;
      }
      var index = -1,
          indexes = [],
          length = array.length;

      predicate = getCallback(predicate, thisArg, 3);
      while (++index < length) {
        var value = array[index];
        if (predicate(value, index, array)) {
          result.push(value);
          indexes.push(index);
        }
      }
      basePullAt(array, indexes);
      return result;
    }

    /**
     * Gets all but the first element of `array`.
     *
     * @static
     * @memberOf _
     * @alias tail
     * @category Array
     * @param {Array} array The array to query.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.rest([1, 2, 3]);
     * // => [2, 3]
     */
    function rest(array) {
      return drop(array, 1);
    }

    /**
     * Creates a slice of `array` from `start` up to, but not including, `end`.
     *
     * **Note:** This method is used instead of `Array#slice` to support node
     * lists in IE < 9 and to ensure dense arrays are returned.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to slice.
     * @param {number} [start=0] The start position.
     * @param {number} [end=array.length] The end position.
     * @returns {Array} Returns the slice of `array`.
     */
    function slice(array, start, end) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (end && typeof end != 'number' && isIterateeCall(array, start, end)) {
        start = 0;
        end = length;
      }
      return baseSlice(array, start, end);
    }

    /**
     * Uses a binary search to determine the lowest index at which `value` should
     * be inserted into `array` in order to maintain its sort order. If an iteratee
     * function is provided it is invoked for `value` and each element of `array`
     * to compute their sort ranking. The iteratee is bound to `thisArg` and
     * invoked with one argument; (value).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The sorted array to inspect.
     * @param {*} value The value to evaluate.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {number} Returns the index at which `value` should be inserted
     *  into `array`.
     * @example
     *
     * _.sortedIndex([30, 50], 40);
     * // => 1
     *
     * _.sortedIndex([4, 4, 5, 5], 5);
     * // => 2
     *
     * var dict = { 'data': { 'thirty': 30, 'forty': 40, 'fifty': 50 } };
     *
     * // using an iteratee function
     * _.sortedIndex(['thirty', 'fifty'], 'forty', function(word) {
     *   return this.data[word];
     * }, dict);
     * // => 1
     *
     * // using the `_.property` callback shorthand
     * _.sortedIndex([{ 'x': 30 }, { 'x': 50 }], { 'x': 40 }, 'x');
     * // => 1
     */
    var sortedIndex = createSortedIndex();

    /**
     * This method is like `_.sortedIndex` except that it returns the highest
     * index at which `value` should be inserted into `array` in order to
     * maintain its sort order.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The sorted array to inspect.
     * @param {*} value The value to evaluate.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {number} Returns the index at which `value` should be inserted
     *  into `array`.
     * @example
     *
     * _.sortedLastIndex([4, 4, 5, 5], 5);
     * // => 4
     */
    var sortedLastIndex = createSortedIndex(true);

    /**
     * Creates a slice of `array` with `n` elements taken from the beginning.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to take.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.take([1, 2, 3]);
     * // => [1]
     *
     * _.take([1, 2, 3], 2);
     * // => [1, 2]
     *
     * _.take([1, 2, 3], 5);
     * // => [1, 2, 3]
     *
     * _.take([1, 2, 3], 0);
     * // => []
     */
    function take(array, n, guard) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (guard ? isIterateeCall(array, n, guard) : n == null) {
        n = 1;
      }
      return baseSlice(array, 0, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` with `n` elements taken from the end.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to take.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.takeRight([1, 2, 3]);
     * // => [3]
     *
     * _.takeRight([1, 2, 3], 2);
     * // => [2, 3]
     *
     * _.takeRight([1, 2, 3], 5);
     * // => [1, 2, 3]
     *
     * _.takeRight([1, 2, 3], 0);
     * // => []
     */
    function takeRight(array, n, guard) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (guard ? isIterateeCall(array, n, guard) : n == null) {
        n = 1;
      }
      n = length - (+n || 0);
      return baseSlice(array, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` with elements taken from the end. Elements are
     * taken until `predicate` returns falsey. The predicate is bound to `thisArg`
     * and invoked with three arguments: (value, index, array).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.takeRightWhile([1, 2, 3], function(n) {
     *   return n > 1;
     * });
     * // => [2, 3]
     *
     * var users = [
     *   { 'user': 'barney',  'active': true },
     *   { 'user': 'fred',    'active': false },
     *   { 'user': 'pebbles', 'active': false }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.takeRightWhile(users, { 'user': 'pebbles', 'active': false }), 'user');
     * // => ['pebbles']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.takeRightWhile(users, 'active', false), 'user');
     * // => ['fred', 'pebbles']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.takeRightWhile(users, 'active'), 'user');
     * // => []
     */
    function takeRightWhile(array, predicate, thisArg) {
      return (array && array.length)
        ? baseWhile(array, getCallback(predicate, thisArg, 3), false, true)
        : [];
    }

    /**
     * Creates a slice of `array` with elements taken from the beginning. Elements
     * are taken until `predicate` returns falsey. The predicate is bound to
     * `thisArg` and invoked with three arguments: (value, index, array).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.takeWhile([1, 2, 3], function(n) {
     *   return n < 3;
     * });
     * // => [1, 2]
     *
     * var users = [
     *   { 'user': 'barney',  'active': false },
     *   { 'user': 'fred',    'active': false},
     *   { 'user': 'pebbles', 'active': true }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.takeWhile(users, { 'user': 'barney', 'active': false }), 'user');
     * // => ['barney']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.takeWhile(users, 'active', false), 'user');
     * // => ['barney', 'fred']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.takeWhile(users, 'active'), 'user');
     * // => []
     */
    function takeWhile(array, predicate, thisArg) {
      return (array && array.length)
        ? baseWhile(array, getCallback(predicate, thisArg, 3))
        : [];
    }

    /**
     * Creates an array of unique values, in order, from all of the provided arrays
     * using [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for equality comparisons.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to inspect.
     * @returns {Array} Returns the new array of combined values.
     * @example
     *
     * _.union([1, 2], [4, 2], [2, 1]);
     * // => [1, 2, 4]
     */
    var union = restParam(function(arrays) {
      return baseUniq(baseFlatten(arrays, false, true));
    });

    /**
     * Creates a duplicate-free version of an array, using
     * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for equality comparisons, in which only the first occurence of each element
     * is kept. Providing `true` for `isSorted` performs a faster search algorithm
     * for sorted arrays. If an iteratee function is provided it is invoked for
     * each element in the array to generate the criterion by which uniqueness
     * is computed. The `iteratee` is bound to `thisArg` and invoked with three
     * arguments: (value, index, array).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @alias unique
     * @category Array
     * @param {Array} array The array to inspect.
     * @param {boolean} [isSorted] Specify the array is sorted.
     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the new duplicate-value-free array.
     * @example
     *
     * _.uniq([2, 1, 2]);
     * // => [2, 1]
     *
     * // using `isSorted`
     * _.uniq([1, 1, 2], true);
     * // => [1, 2]
     *
     * // using an iteratee function
     * _.uniq([1, 2.5, 1.5, 2], function(n) {
     *   return this.floor(n);
     * }, Math);
     * // => [1, 2.5]
     *
     * // using the `_.property` callback shorthand
     * _.uniq([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
     * // => [{ 'x': 1 }, { 'x': 2 }]
     */
    function uniq(array, isSorted, iteratee, thisArg) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (isSorted != null && typeof isSorted != 'boolean') {
        thisArg = iteratee;
        iteratee = isIterateeCall(array, isSorted, thisArg) ? null : isSorted;
        isSorted = false;
      }
      var callback = getCallback();
      if (!(iteratee == null && callback === baseCallback)) {
        iteratee = callback(iteratee, thisArg, 3);
      }
      return (isSorted && getIndexOf() == baseIndexOf)
        ? sortedUniq(array, iteratee)
        : baseUniq(array, iteratee);
    }

    /**
     * This method is like `_.zip` except that it accepts an array of grouped
     * elements and creates an array regrouping the elements to their pre-zip
     * configuration.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array of grouped elements to process.
     * @returns {Array} Returns the new array of regrouped elements.
     * @example
     *
     * var zipped = _.zip(['fred', 'barney'], [30, 40], [true, false]);
     * // => [['fred', 30, true], ['barney', 40, false]]
     *
     * _.unzip(zipped);
     * // => [['fred', 'barney'], [30, 40], [true, false]]
     */
    function unzip(array) {
      if (!(array && array.length)) {
        return [];
      }
      var index = -1,
          length = 0;

      array = arrayFilter(array, function(group) {
        if (isArrayLike(group)) {
          length = nativeMax(group.length, length);
          return true;
        }
      });
      var result = Array(length);
      while (++index < length) {
        result[index] = arrayMap(array, baseProperty(index));
      }
      return result;
    }

    /**
     * This method is like `_.unzip` except that it accepts an iteratee to specify
     * how regrouped values should be combined. The `iteratee` is bound to `thisArg`
     * and invoked with four arguments: (accumulator, value, index, group).
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array of grouped elements to process.
     * @param {Function} [iteratee] The function to combine regrouped values.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the new array of regrouped elements.
     * @example
     *
     * var zipped = _.zip([1, 2], [10, 20], [100, 200]);
     * // => [[1, 10, 100], [2, 20, 200]]
     *
     * _.unzipWith(zipped, _.add);
     * // => [3, 30, 300]
     */
    function unzipWith(array, iteratee, thisArg) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      var result = unzip(array);
      if (iteratee == null) {
        return result;
      }
      iteratee = bindCallback(iteratee, thisArg, 4);
      return arrayMap(result, function(group) {
        return arrayReduce(group, iteratee, undefined, true);
      });
    }

    /**
     * Creates an array excluding all provided values using
     * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for equality comparisons.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to filter.
     * @param {...*} [values] The values to exclude.
     * @returns {Array} Returns the new array of filtered values.
     * @example
     *
     * _.without([1, 2, 1, 3], 1, 2);
     * // => [3]
     */
    var without = restParam(function(array, values) {
      return isArrayLike(array)
        ? baseDifference(array, values)
        : [];
    });

    /**
     * Creates an array of unique values that is the [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
     * of the provided arrays.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to inspect.
     * @returns {Array} Returns the new array of values.
     * @example
     *
     * _.xor([1, 2], [4, 2]);
     * // => [1, 4]
     */
    function xor() {
      var index = -1,
          length = arguments.length;

      while (++index < length) {
        var array = arguments[index];
        if (isArrayLike(array)) {
          var result = result
            ? baseDifference(result, array).concat(baseDifference(array, result))
            : array;
        }
      }
      return result ? baseUniq(result) : [];
    }

    /**
     * Creates an array of grouped elements, the first of which contains the first
     * elements of the given arrays, the second of which contains the second elements
     * of the given arrays, and so on.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to process.
     * @returns {Array} Returns the new array of grouped elements.
     * @example
     *
     * _.zip(['fred', 'barney'], [30, 40], [true, false]);
     * // => [['fred', 30, true], ['barney', 40, false]]
     */
    var zip = restParam(unzip);

    /**
     * The inverse of `_.pairs`; this method returns an object composed from arrays
     * of property names and values. Provide either a single two dimensional array,
     * e.g. `[[key1, value1], [key2, value2]]` or two arrays, one of property names
     * and one of corresponding values.
     *
     * @static
     * @memberOf _
     * @alias object
     * @category Array
     * @param {Array} props The property names.
     * @param {Array} [values=[]] The property values.
     * @returns {Object} Returns the new object.
     * @example
     *
     * _.zipObject([['fred', 30], ['barney', 40]]);
     * // => { 'fred': 30, 'barney': 40 }
     *
     * _.zipObject(['fred', 'barney'], [30, 40]);
     * // => { 'fred': 30, 'barney': 40 }
     */
    function zipObject(props, values) {
      var index = -1,
          length = props ? props.length : 0,
          result = {};

      if (length && !values && !isArray(props[0])) {
        values = [];
      }
      while (++index < length) {
        var key = props[index];
        if (values) {
          result[key] = values[index];
        } else if (key) {
          result[key[0]] = key[1];
        }
      }
      return result;
    }

    /**
     * This method is like `_.zip` except that it accepts an iteratee to specify
     * how grouped values should be combined. The `iteratee` is bound to `thisArg`
     * and invoked with four arguments: (accumulator, value, index, group).
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to process.
     * @param {Function} [iteratee] The function to combine grouped values.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the new array of grouped elements.
     * @example
     *
     * _.zipWith([1, 2], [10, 20], [100, 200], _.add);
     * // => [111, 222]
     */
    var zipWith = restParam(function(arrays) {
      var length = arrays.length,
          iteratee = length > 2 ? arrays[length - 2] : undefined,
          thisArg = length > 1 ? arrays[length - 1] : undefined;

      if (length > 2 && typeof iteratee == 'function') {
        length -= 2;
      } else {
        iteratee = (length > 1 && typeof thisArg == 'function') ? (--length, thisArg) : undefined;
        thisArg = undefined;
      }
      arrays.length = length;
      return unzipWith(arrays, iteratee, thisArg);
    });

    /*------------------------------------------------------------------------*/

    /**
     * Creates a `lodash` object that wraps `value` with explicit method
     * chaining enabled.
     *
     * @static
     * @memberOf _
     * @category Chain
     * @param {*} value The value to wrap.
     * @returns {Object} Returns the new `lodash` wrapper instance.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36 },
     *   { 'user': 'fred',    'age': 40 },
     *   { 'user': 'pebbles', 'age': 1 }
     * ];
     *
     * var youngest = _.chain(users)
     *   .sortBy('age')
     *   .map(function(chr) {
     *     return chr.user + ' is ' + chr.age;
     *   })
     *   .first()
     *   .value();
     * // => 'pebbles is 1'
     */
    function chain(value) {
      var result = lodash(value);
      result.__chain__ = true;
      return result;
    }

    /**
     * This method invokes `interceptor` and returns `value`. The interceptor is
     * bound to `thisArg` and invoked with one argument; (value). The purpose of
     * this method is to "tap into" a method chain in order to perform operations
     * on intermediate results within the chain.
     *
     * @static
     * @memberOf _
     * @category Chain
     * @param {*} value The value to provide to `interceptor`.
     * @param {Function} interceptor The function to invoke.
     * @param {*} [thisArg] The `this` binding of `interceptor`.
     * @returns {*} Returns `value`.
     * @example
     *
     * _([1, 2, 3])
     *  .tap(function(array) {
     *    array.pop();
     *  })
     *  .reverse()
     *  .value();
     * // => [2, 1]
     */
    function tap(value, interceptor, thisArg) {
      interceptor.call(thisArg, value);
      return value;
    }

    /**
     * This method is like `_.tap` except that it returns the result of `interceptor`.
     *
     * @static
     * @memberOf _
     * @category Chain
     * @param {*} value The value to provide to `interceptor`.
     * @param {Function} interceptor The function to invoke.
     * @param {*} [thisArg] The `this` binding of `interceptor`.
     * @returns {*} Returns the result of `interceptor`.
     * @example
     *
     * _('  abc  ')
     *  .chain()
     *  .trim()
     *  .thru(function(value) {
     *    return [value];
     *  })
     *  .value();
     * // => ['abc']
     */
    function thru(value, interceptor, thisArg) {
      return interceptor.call(thisArg, value);
    }

    /**
     * Enables explicit method chaining on the wrapper object.
     *
     * @name chain
     * @memberOf _
     * @category Chain
     * @returns {Object} Returns the new `lodash` wrapper instance.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * // without explicit chaining
     * _(users).first();
     * // => { 'user': 'barney', 'age': 36 }
     *
     * // with explicit chaining
     * _(users).chain()
     *   .first()
     *   .pick('user')
     *   .value();
     * // => { 'user': 'barney' }
     */
    function wrapperChain() {
      return chain(this);
    }

    /**
     * Executes the chained sequence and returns the wrapped result.
     *
     * @name commit
     * @memberOf _
     * @category Chain
     * @returns {Object} Returns the new `lodash` wrapper instance.
     * @example
     *
     * var array = [1, 2];
     * var wrapper = _(array).push(3);
     *
     * console.log(array);
     * // => [1, 2]
     *
     * wrapper = wrapper.commit();
     * console.log(array);
     * // => [1, 2, 3]
     *
     * wrapper.last();
     * // => 3
     *
     * console.log(array);
     * // => [1, 2, 3]
     */
    function wrapperCommit() {
      return new LodashWrapper(this.value(), this.__chain__);
    }

    /**
     * Creates a clone of the chained sequence planting `value` as the wrapped value.
     *
     * @name plant
     * @memberOf _
     * @category Chain
     * @returns {Object} Returns the new `lodash` wrapper instance.
     * @example
     *
     * var array = [1, 2];
     * var wrapper = _(array).map(function(value) {
     *   return Math.pow(value, 2);
     * });
     *
     * var other = [3, 4];
     * var otherWrapper = wrapper.plant(other);
     *
     * otherWrapper.value();
     * // => [9, 16]
     *
     * wrapper.value();
     * // => [1, 4]
     */
    function wrapperPlant(value) {
      var result,
          parent = this;

      while (parent instanceof baseLodash) {
        var clone = wrapperClone(parent);
        if (result) {
          previous.__wrapped__ = clone;
        } else {
          result = clone;
        }
        var previous = clone;
        parent = parent.__wrapped__;
      }
      previous.__wrapped__ = value;
      return result;
    }

    /**
     * Reverses the wrapped array so the first element becomes the last, the
     * second element becomes the second to last, and so on.
     *
     * **Note:** This method mutates the wrapped array.
     *
     * @name reverse
     * @memberOf _
     * @category Chain
     * @returns {Object} Returns the new reversed `lodash` wrapper instance.
     * @example
     *
     * var array = [1, 2, 3];
     *
     * _(array).reverse().value()
     * // => [3, 2, 1]
     *
     * console.log(array);
     * // => [3, 2, 1]
     */
    function wrapperReverse() {
      var value = this.__wrapped__;
      if (value instanceof LazyWrapper) {
        if (this.__actions__.length) {
          value = new LazyWrapper(this);
        }
        return new LodashWrapper(value.reverse(), this.__chain__);
      }
      return this.thru(function(value) {
        return value.reverse();
      });
    }

    /**
     * Produces the result of coercing the unwrapped value to a string.
     *
     * @name toString
     * @memberOf _
     * @category Chain
     * @returns {string} Returns the coerced string value.
     * @example
     *
     * _([1, 2, 3]).toString();
     * // => '1,2,3'
     */
    function wrapperToString() {
      return (this.value() + '');
    }

    /**
     * Executes the chained sequence to extract the unwrapped value.
     *
     * @name value
     * @memberOf _
     * @alias run, toJSON, valueOf
     * @category Chain
     * @returns {*} Returns the resolved unwrapped value.
     * @example
     *
     * _([1, 2, 3]).value();
     * // => [1, 2, 3]
     */
    function wrapperValue() {
      return baseWrapperValue(this.__wrapped__, this.__actions__);
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates an array of elements corresponding to the given keys, or indexes,
     * of `collection`. Keys may be specified as individual arguments or as arrays
     * of keys.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {...(number|number[]|string|string[])} [props] The property names
     *  or indexes of elements to pick, specified individually or in arrays.
     * @returns {Array} Returns the new array of picked elements.
     * @example
     *
     * _.at(['a', 'b', 'c'], [0, 2]);
     * // => ['a', 'c']
     *
     * _.at(['barney', 'fred', 'pebbles'], 0, 2);
     * // => ['barney', 'pebbles']
     */
    var at = restParam(function(collection, props) {
      return baseAt(collection, baseFlatten(props));
    });

    /**
     * Creates an object composed of keys generated from the results of running
     * each element of `collection` through `iteratee`. The corresponding value
     * of each key is the number of times the key was returned by `iteratee`.
     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the composed aggregate object.
     * @example
     *
     * _.countBy([4.3, 6.1, 6.4], function(n) {
     *   return Math.floor(n);
     * });
     * // => { '4': 1, '6': 2 }
     *
     * _.countBy([4.3, 6.1, 6.4], function(n) {
     *   return this.floor(n);
     * }, Math);
     * // => { '4': 1, '6': 2 }
     *
     * _.countBy(['one', 'two', 'three'], 'length');
     * // => { '3': 2, '5': 1 }
     */
    var countBy = createAggregator(function(result, value, key) {
      hasOwnProperty.call(result, key) ? ++result[key] : (result[key] = 1);
    });

    /**
     * Checks if `predicate` returns truthy for **all** elements of `collection`.
     * The predicate is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @alias all
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {boolean} Returns `true` if all elements pass the predicate check,
     *  else `false`.
     * @example
     *
     * _.every([true, 1, null, 'yes'], Boolean);
     * // => false
     *
     * var users = [
     *   { 'user': 'barney', 'active': false },
     *   { 'user': 'fred',   'active': false }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.every(users, { 'user': 'barney', 'active': false });
     * // => false
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.every(users, 'active', false);
     * // => true
     *
     * // using the `_.property` callback shorthand
     * _.every(users, 'active');
     * // => false
     */
    function every(collection, predicate, thisArg) {
      var func = isArray(collection) ? arrayEvery : baseEvery;
      if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
        predicate = null;
      }
      if (typeof predicate != 'function' || thisArg !== undefined) {
        predicate = getCallback(predicate, thisArg, 3);
      }
      return func(collection, predicate);
    }

    /**
     * Iterates over elements of `collection`, returning an array of all elements
     * `predicate` returns truthy for. The predicate is bound to `thisArg` and
     * invoked with three arguments: (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @alias select
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the new filtered array.
     * @example
     *
     * _.filter([4, 5, 6], function(n) {
     *   return n % 2 == 0;
     * });
     * // => [4, 6]
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'active': true },
     *   { 'user': 'fred',   'age': 40, 'active': false }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.filter(users, { 'age': 36, 'active': true }), 'user');
     * // => ['barney']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.filter(users, 'active', false), 'user');
     * // => ['fred']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.filter(users, 'active'), 'user');
     * // => ['barney']
     */
    function filter(collection, predicate, thisArg) {
      var func = isArray(collection) ? arrayFilter : baseFilter;
      predicate = getCallback(predicate, thisArg, 3);
      return func(collection, predicate);
    }

    /**
     * Iterates over elements of `collection`, returning the first element
     * `predicate` returns truthy for. The predicate is bound to `thisArg` and
     * invoked with three arguments: (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @alias detect
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {*} Returns the matched element, else `undefined`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36, 'active': true },
     *   { 'user': 'fred',    'age': 40, 'active': false },
     *   { 'user': 'pebbles', 'age': 1,  'active': true }
     * ];
     *
     * _.result(_.find(users, function(chr) {
     *   return chr.age < 40;
     * }), 'user');
     * // => 'barney'
     *
     * // using the `_.matches` callback shorthand
     * _.result(_.find(users, { 'age': 1, 'active': true }), 'user');
     * // => 'pebbles'
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.result(_.find(users, 'active', false), 'user');
     * // => 'fred'
     *
     * // using the `_.property` callback shorthand
     * _.result(_.find(users, 'active'), 'user');
     * // => 'barney'
     */
    var find = createFind(baseEach);

    /**
     * This method is like `_.find` except that it iterates over elements of
     * `collection` from right to left.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {*} Returns the matched element, else `undefined`.
     * @example
     *
     * _.findLast([1, 2, 3, 4], function(n) {
     *   return n % 2 == 1;
     * });
     * // => 3
     */
    var findLast = createFind(baseEachRight, true);

    /**
     * Performs a deep comparison between each element in `collection` and the
     * source object, returning the first element that has equivalent property
     * values.
     *
     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
     * numbers, `Object` objects, regexes, and strings. Objects are compared by
     * their own, not inherited, enumerable properties. For comparing a single
     * own or inherited property value see `_.matchesProperty`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Object} source The object of property values to match.
     * @returns {*} Returns the matched element, else `undefined`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'active': true },
     *   { 'user': 'fred',   'age': 40, 'active': false }
     * ];
     *
     * _.result(_.findWhere(users, { 'age': 36, 'active': true }), 'user');
     * // => 'barney'
     *
     * _.result(_.findWhere(users, { 'age': 40, 'active': false }), 'user');
     * // => 'fred'
     */
    function findWhere(collection, source) {
      return find(collection, baseMatches(source));
    }

    /**
     * Iterates over elements of `collection` invoking `iteratee` for each element.
     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection). Iteratee functions may exit iteration early
     * by explicitly returning `false`.
     *
     * **Note:** As with other "Collections" methods, objects with a "length" property
     * are iterated like arrays. To avoid this behavior `_.forIn` or `_.forOwn`
     * may be used for object iteration.
     *
     * @static
     * @memberOf _
     * @alias each
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array|Object|string} Returns `collection`.
     * @example
     *
     * _([1, 2]).forEach(function(n) {
     *   console.log(n);
     * }).value();
     * // => logs each value from left to right and returns the array
     *
     * _.forEach({ 'a': 1, 'b': 2 }, function(n, key) {
     *   console.log(n, key);
     * });
     * // => logs each value-key pair and returns the object (iteration order is not guaranteed)
     */
    var forEach = createForEach(arrayEach, baseEach);

    /**
     * This method is like `_.forEach` except that it iterates over elements of
     * `collection` from right to left.
     *
     * @static
     * @memberOf _
     * @alias eachRight
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array|Object|string} Returns `collection`.
     * @example
     *
     * _([1, 2]).forEachRight(function(n) {
     *   console.log(n);
     * }).value();
     * // => logs each value from right to left and returns the array
     */
    var forEachRight = createForEach(arrayEachRight, baseEachRight);

    /**
     * Creates an object composed of keys generated from the results of running
     * each element of `collection` through `iteratee`. The corresponding value
     * of each key is an array of the elements responsible for generating the key.
     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the composed aggregate object.
     * @example
     *
     * _.groupBy([4.2, 6.1, 6.4], function(n) {
     *   return Math.floor(n);
     * });
     * // => { '4': [4.2], '6': [6.1, 6.4] }
     *
     * _.groupBy([4.2, 6.1, 6.4], function(n) {
     *   return this.floor(n);
     * }, Math);
     * // => { '4': [4.2], '6': [6.1, 6.4] }
     *
     * // using the `_.property` callback shorthand
     * _.groupBy(['one', 'two', 'three'], 'length');
     * // => { '3': ['one', 'two'], '5': ['three'] }
     */
    var groupBy = createAggregator(function(result, value, key) {
      if (hasOwnProperty.call(result, key)) {
        result[key].push(value);
      } else {
        result[key] = [value];
      }
    });

    /**
     * Checks if `value` is in `collection` using
     * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for equality comparisons. If `fromIndex` is negative, it is used as the offset
     * from the end of `collection`.
     *
     * @static
     * @memberOf _
     * @alias contains, include
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {*} target The value to search for.
     * @param {number} [fromIndex=0] The index to search from.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
     * @returns {boolean} Returns `true` if a matching element is found, else `false`.
     * @example
     *
     * _.includes([1, 2, 3], 1);
     * // => true
     *
     * _.includes([1, 2, 3], 1, 2);
     * // => false
     *
     * _.includes({ 'user': 'fred', 'age': 40 }, 'fred');
     * // => true
     *
     * _.includes('pebbles', 'eb');
     * // => true
     */
    function includes(collection, target, fromIndex, guard) {
      var length = collection ? getLength(collection) : 0;
      if (!isLength(length)) {
        collection = values(collection);
        length = collection.length;
      }
      if (!length) {
        return false;
      }
      if (typeof fromIndex != 'number' || (guard && isIterateeCall(target, fromIndex, guard))) {
        fromIndex = 0;
      } else {
        fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : (fromIndex || 0);
      }
      return (typeof collection == 'string' || !isArray(collection) && isString(collection))
        ? (fromIndex < length && collection.indexOf(target, fromIndex) > -1)
        : (getIndexOf(collection, target, fromIndex) > -1);
    }

    /**
     * Creates an object composed of keys generated from the results of running
     * each element of `collection` through `iteratee`. The corresponding value
     * of each key is the last element responsible for generating the key. The
     * iteratee function is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the composed aggregate object.
     * @example
     *
     * var keyData = [
     *   { 'dir': 'left', 'code': 97 },
     *   { 'dir': 'right', 'code': 100 }
     * ];
     *
     * _.indexBy(keyData, 'dir');
     * // => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }
     *
     * _.indexBy(keyData, function(object) {
     *   return String.fromCharCode(object.code);
     * });
     * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
     *
     * _.indexBy(keyData, function(object) {
     *   return this.fromCharCode(object.code);
     * }, String);
     * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
     */
    var indexBy = createAggregator(function(result, value, key) {
      result[key] = value;
    });

    /**
     * Invokes the method at `path` of each element in `collection`, returning
     * an array of the results of each invoked method. Any additional arguments
     * are provided to each invoked method. If `methodName` is a function it is
     * invoked for, and `this` bound to, each element in `collection`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Array|Function|string} path The path of the method to invoke or
     *  the function invoked per iteration.
     * @param {...*} [args] The arguments to invoke the method with.
     * @returns {Array} Returns the array of results.
     * @example
     *
     * _.invoke([[5, 1, 7], [3, 2, 1]], 'sort');
     * // => [[1, 5, 7], [1, 2, 3]]
     *
     * _.invoke([123, 456], String.prototype.split, '');
     * // => [['1', '2', '3'], ['4', '5', '6']]
     */
    var invoke = restParam(function(collection, path, args) {
      var index = -1,
          isFunc = typeof path == 'function',
          isProp = isKey(path),
          result = isArrayLike(collection) ? Array(collection.length) : [];

      baseEach(collection, function(value) {
        var func = isFunc ? path : ((isProp && value != null) ? value[path] : null);
        result[++index] = func ? func.apply(value, args) : invokePath(value, path, args);
      });
      return result;
    });

    /**
     * Creates an array of values by running each element in `collection` through
     * `iteratee`. The `iteratee` is bound to `thisArg` and invoked with three
     * arguments: (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * Many lodash methods are guarded to work as iteratees for methods like
     * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
     *
     * The guarded methods are:
     * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`,
     * `drop`, `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`,
     * `parseInt`, `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`,
     * `trimLeft`, `trimRight`, `trunc`, `random`, `range`, `sample`, `some`,
     * `sum`, `uniq`, and `words`
     *
     * @static
     * @memberOf _
     * @alias collect
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the new mapped array.
     * @example
     *
     * function timesThree(n) {
     *   return n * 3;
     * }
     *
     * _.map([1, 2], timesThree);
     * // => [3, 6]
     *
     * _.map({ 'a': 1, 'b': 2 }, timesThree);
     * // => [3, 6] (iteration order is not guaranteed)
     *
     * var users = [
     *   { 'user': 'barney' },
     *   { 'user': 'fred' }
     * ];
     *
     * // using the `_.property` callback shorthand
     * _.map(users, 'user');
     * // => ['barney', 'fred']
     */
    function map(collection, iteratee, thisArg) {
      var func = isArray(collection) ? arrayMap : baseMap;
      iteratee = getCallback(iteratee, thisArg, 3);
      return func(collection, iteratee);
    }

    /**
     * Creates an array of elements split into two groups, the first of which
     * contains elements `predicate` returns truthy for, while the second of which
     * contains elements `predicate` returns falsey for. The predicate is bound
     * to `thisArg` and invoked with three arguments: (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the array of grouped elements.
     * @example
     *
     * _.partition([1, 2, 3], function(n) {
     *   return n % 2;
     * });
     * // => [[1, 3], [2]]
     *
     * _.partition([1.2, 2.3, 3.4], function(n) {
     *   return this.floor(n) % 2;
     * }, Math);
     * // => [[1.2, 3.4], [2.3]]
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36, 'active': false },
     *   { 'user': 'fred',    'age': 40, 'active': true },
     *   { 'user': 'pebbles', 'age': 1,  'active': false }
     * ];
     *
     * var mapper = function(array) {
     *   return _.pluck(array, 'user');
     * };
     *
     * // using the `_.matches` callback shorthand
     * _.map(_.partition(users, { 'age': 1, 'active': false }), mapper);
     * // => [['pebbles'], ['barney', 'fred']]
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.map(_.partition(users, 'active', false), mapper);
     * // => [['barney', 'pebbles'], ['fred']]
     *
     * // using the `_.property` callback shorthand
     * _.map(_.partition(users, 'active'), mapper);
     * // => [['fred'], ['barney', 'pebbles']]
     */
    var partition = createAggregator(function(result, value, key) {
      result[key ? 0 : 1].push(value);
    }, function() { return [[], []]; });

    /**
     * Gets the property value of `path` from all elements in `collection`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Array|string} path The path of the property to pluck.
     * @returns {Array} Returns the property values.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * _.pluck(users, 'user');
     * // => ['barney', 'fred']
     *
     * var userIndex = _.indexBy(users, 'user');
     * _.pluck(userIndex, 'age');
     * // => [36, 40] (iteration order is not guaranteed)
     */
    function pluck(collection, path) {
      return map(collection, property(path));
    }

    /**
     * Reduces `collection` to a value which is the accumulated result of running
     * each element in `collection` through `iteratee`, where each successive
     * invocation is supplied the return value of the previous. If `accumulator`
     * is not provided the first element of `collection` is used as the initial
     * value. The `iteratee` is bound to `thisArg` and invoked with four arguments:
     * (accumulator, value, index|key, collection).
     *
     * Many lodash methods are guarded to work as iteratees for methods like
     * `_.reduce`, `_.reduceRight`, and `_.transform`.
     *
     * The guarded methods are:
     * `assign`, `defaults`, `includes`, `merge`, `sortByAll`, and `sortByOrder`
     *
     * @static
     * @memberOf _
     * @alias foldl, inject
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [accumulator] The initial value.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the accumulated value.
     * @example
     *
     * _.reduce([1, 2], function(total, n) {
     *   return total + n;
     * });
     * // => 3
     *
     * _.reduce({ 'a': 1, 'b': 2 }, function(result, n, key) {
     *   result[key] = n * 3;
     *   return result;
     * }, {});
     * // => { 'a': 3, 'b': 6 } (iteration order is not guaranteed)
     */
    var reduce = createReduce(arrayReduce, baseEach);

    /**
     * This method is like `_.reduce` except that it iterates over elements of
     * `collection` from right to left.
     *
     * @static
     * @memberOf _
     * @alias foldr
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [accumulator] The initial value.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the accumulated value.
     * @example
     *
     * var array = [[0, 1], [2, 3], [4, 5]];
     *
     * _.reduceRight(array, function(flattened, other) {
     *   return flattened.concat(other);
     * }, []);
     * // => [4, 5, 2, 3, 0, 1]
     */
    var reduceRight = createReduce(arrayReduceRight, baseEachRight);

    /**
     * The opposite of `_.filter`; this method returns the elements of `collection`
     * that `predicate` does **not** return truthy for.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the new filtered array.
     * @example
     *
     * _.reject([1, 2, 3, 4], function(n) {
     *   return n % 2 == 0;
     * });
     * // => [1, 3]
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'active': false },
     *   { 'user': 'fred',   'age': 40, 'active': true }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.reject(users, { 'age': 40, 'active': true }), 'user');
     * // => ['barney']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.reject(users, 'active', false), 'user');
     * // => ['fred']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.reject(users, 'active'), 'user');
     * // => ['barney']
     */
    function reject(collection, predicate, thisArg) {
      var func = isArray(collection) ? arrayFilter : baseFilter;
      predicate = getCallback(predicate, thisArg, 3);
      return func(collection, function(value, index, collection) {
        return !predicate(value, index, collection);
      });
    }

    /**
     * Gets a random element or `n` random elements from a collection.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to sample.
     * @param {number} [n] The number of elements to sample.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {*} Returns the random sample(s).
     * @example
     *
     * _.sample([1, 2, 3, 4]);
     * // => 2
     *
     * _.sample([1, 2, 3, 4], 2);
     * // => [3, 1]
     */
    function sample(collection, n, guard) {
      if (guard ? isIterateeCall(collection, n, guard) : n == null) {
        collection = toIterable(collection);
        var length = collection.length;
        return length > 0 ? collection[baseRandom(0, length - 1)] : undefined;
      }
      var index = -1,
          result = toArray(collection),
          length = result.length,
          lastIndex = length - 1;

      n = nativeMin(n < 0 ? 0 : (+n || 0), length);
      while (++index < n) {
        var rand = baseRandom(index, lastIndex),
            value = result[rand];

        result[rand] = result[index];
        result[index] = value;
      }
      result.length = n;
      return result;
    }

    /**
     * Creates an array of shuffled values, using a version of the
     * [Fisher-Yates shuffle](https://en.wikipedia.org/wiki/Fisher-Yates_shuffle).
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to shuffle.
     * @returns {Array} Returns the new shuffled array.
     * @example
     *
     * _.shuffle([1, 2, 3, 4]);
     * // => [4, 1, 3, 2]
     */
    function shuffle(collection) {
      return sample(collection, POSITIVE_INFINITY);
    }

    /**
     * Gets the size of `collection` by returning its length for array-like
     * values or the number of own enumerable properties for objects.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to inspect.
     * @returns {number} Returns the size of `collection`.
     * @example
     *
     * _.size([1, 2, 3]);
     * // => 3
     *
     * _.size({ 'a': 1, 'b': 2 });
     * // => 2
     *
     * _.size('pebbles');
     * // => 7
     */
    function size(collection) {
      var length = collection ? getLength(collection) : 0;
      return isLength(length) ? length : keys(collection).length;
    }

    /**
     * Checks if `predicate` returns truthy for **any** element of `collection`.
     * The function returns as soon as it finds a passing value and does not iterate
     * over the entire collection. The predicate is bound to `thisArg` and invoked
     * with three arguments: (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @alias any
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {boolean} Returns `true` if any element passes the predicate check,
     *  else `false`.
     * @example
     *
     * _.some([null, 0, 'yes', false], Boolean);
     * // => true
     *
     * var users = [
     *   { 'user': 'barney', 'active': true },
     *   { 'user': 'fred',   'active': false }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.some(users, { 'user': 'barney', 'active': false });
     * // => false
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.some(users, 'active', false);
     * // => true
     *
     * // using the `_.property` callback shorthand
     * _.some(users, 'active');
     * // => true
     */
    function some(collection, predicate, thisArg) {
      var func = isArray(collection) ? arraySome : baseSome;
      if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
        predicate = null;
      }
      if (typeof predicate != 'function' || thisArg !== undefined) {
        predicate = getCallback(predicate, thisArg, 3);
      }
      return func(collection, predicate);
    }

    /**
     * Creates an array of elements, sorted in ascending order by the results of
     * running each element in a collection through `iteratee`. This method performs
     * a stable sort, that is, it preserves the original sort order of equal elements.
     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the new sorted array.
     * @example
     *
     * _.sortBy([1, 2, 3], function(n) {
     *   return Math.sin(n);
     * });
     * // => [3, 1, 2]
     *
     * _.sortBy([1, 2, 3], function(n) {
     *   return this.sin(n);
     * }, Math);
     * // => [3, 1, 2]
     *
     * var users = [
     *   { 'user': 'fred' },
     *   { 'user': 'pebbles' },
     *   { 'user': 'barney' }
     * ];
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.sortBy(users, 'user'), 'user');
     * // => ['barney', 'fred', 'pebbles']
     */
    function sortBy(collection, iteratee, thisArg) {
      if (collection == null) {
        return [];
      }
      if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
        iteratee = null;
      }
      var index = -1;
      iteratee = getCallback(iteratee, thisArg, 3);

      var result = baseMap(collection, function(value, key, collection) {
        return { 'criteria': iteratee(value, key, collection), 'index': ++index, 'value': value };
      });
      return baseSortBy(result, compareAscending);
    }

    /**
     * This method is like `_.sortBy` except that it can sort by multiple iteratees
     * or property names.
     *
     * If a property name is provided for an iteratee the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If an object is provided for an iteratee the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {...(Function|Function[]|Object|Object[]|string|string[])} iteratees
     *  The iteratees to sort by, specified as individual values or arrays of values.
     * @returns {Array} Returns the new sorted array.
     * @example
     *
     * var users = [
     *   { 'user': 'fred',   'age': 48 },
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 42 },
     *   { 'user': 'barney', 'age': 34 }
     * ];
     *
     * _.map(_.sortByAll(users, ['user', 'age']), _.values);
     * // => [['barney', 34], ['barney', 36], ['fred', 42], ['fred', 48]]
     *
     * _.map(_.sortByAll(users, 'user', function(chr) {
     *   return Math.floor(chr.age / 10);
     * }), _.values);
     * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
     */
    var sortByAll = restParam(function(collection, iteratees) {
      if (collection == null) {
        return [];
      }
      var guard = iteratees[2];
      if (guard && isIterateeCall(iteratees[0], iteratees[1], guard)) {
        iteratees.length = 1;
      }
      return baseSortByOrder(collection, baseFlatten(iteratees), []);
    });

    /**
     * This method is like `_.sortByAll` except that it allows specifying the
     * sort orders of the iteratees to sort by. A truthy value in `orders` will
     * sort the corresponding property name in ascending order while a falsey
     * value will sort it in descending order.
     *
     * If a property name is provided for an iteratee the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If an object is provided for an iteratee the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
     * @param {boolean[]} orders The sort orders of `iteratees`.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
     * @returns {Array} Returns the new sorted array.
     * @example
     *
     * var users = [
     *   { 'user': 'fred',   'age': 48 },
     *   { 'user': 'barney', 'age': 34 },
     *   { 'user': 'fred',   'age': 42 },
     *   { 'user': 'barney', 'age': 36 }
     * ];
     *
     * // sort by `user` in ascending order and by `age` in descending order
     * _.map(_.sortByOrder(users, ['user', 'age'], [true, false]), _.values);
     * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
     */
    function sortByOrder(collection, iteratees, orders, guard) {
      if (collection == null) {
        return [];
      }
      if (guard && isIterateeCall(iteratees, orders, guard)) {
        orders = null;
      }
      if (!isArray(iteratees)) {
        iteratees = iteratees == null ? [] : [iteratees];
      }
      if (!isArray(orders)) {
        orders = orders == null ? [] : [orders];
      }
      return baseSortByOrder(collection, iteratees, orders);
    }

    /**
     * Performs a deep comparison between each element in `collection` and the
     * source object, returning an array of all elements that have equivalent
     * property values.
     *
     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
     * numbers, `Object` objects, regexes, and strings. Objects are compared by
     * their own, not inherited, enumerable properties. For comparing a single
     * own or inherited property value see `_.matchesProperty`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Object} source The object of property values to match.
     * @returns {Array} Returns the new filtered array.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'active': false, 'pets': ['hoppy'] },
     *   { 'user': 'fred',   'age': 40, 'active': true, 'pets': ['baby puss', 'dino'] }
     * ];
     *
     * _.pluck(_.where(users, { 'age': 36, 'active': false }), 'user');
     * // => ['barney']
     *
     * _.pluck(_.where(users, { 'pets': ['dino'] }), 'user');
     * // => ['fred']
     */
    function where(collection, source) {
      return filter(collection, baseMatches(source));
    }

    /*------------------------------------------------------------------------*/

    /**
     * Gets the number of milliseconds that have elapsed since the Unix epoch
     * (1 January 1970 00:00:00 UTC).
     *
     * @static
     * @memberOf _
     * @category Date
     * @example
     *
     * _.defer(function(stamp) {
     *   console.log(_.now() - stamp);
     * }, _.now());
     * // => logs the number of milliseconds it took for the deferred function to be invoked
     */
    var now = nativeNow || function() {
      return new Date().getTime();
    };

    /*------------------------------------------------------------------------*/

    /**
     * The opposite of `_.before`; this method creates a function that invokes
     * `func` once it is called `n` or more times.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {number} n The number of calls before `func` is invoked.
     * @param {Function} func The function to restrict.
     * @returns {Function} Returns the new restricted function.
     * @example
     *
     * var saves = ['profile', 'settings'];
     *
     * var done = _.after(saves.length, function() {
     *   console.log('done saving!');
     * });
     *
     * _.forEach(saves, function(type) {
     *   asyncSave({ 'type': type, 'complete': done });
     * });
     * // => logs 'done saving!' after the two async saves have completed
     */
    function after(n, func) {
      if (typeof func != 'function') {
        if (typeof n == 'function') {
          var temp = n;
          n = func;
          func = temp;
        } else {
          throw new TypeError(FUNC_ERROR_TEXT);
        }
      }
      n = nativeIsFinite(n = +n) ? n : 0;
      return function() {
        if (--n < 1) {
          return func.apply(this, arguments);
        }
      };
    }

    /**
     * Creates a function that accepts up to `n` arguments ignoring any
     * additional arguments.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to cap arguments for.
     * @param {number} [n=func.length] The arity cap.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Function} Returns the new function.
     * @example
     *
     * _.map(['6', '8', '10'], _.ary(parseInt, 1));
     * // => [6, 8, 10]
     */
    function ary(func, n, guard) {
      if (guard && isIterateeCall(func, n, guard)) {
        n = null;
      }
      n = (func && n == null) ? func.length : nativeMax(+n || 0, 0);
      return createWrapper(func, ARY_FLAG, null, null, null, null, n);
    }

    /**
     * Creates a function that invokes `func`, with the `this` binding and arguments
     * of the created function, while it is called less than `n` times. Subsequent
     * calls to the created function return the result of the last `func` invocation.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {number} n The number of calls at which `func` is no longer invoked.
     * @param {Function} func The function to restrict.
     * @returns {Function} Returns the new restricted function.
     * @example
     *
     * jQuery('#add').on('click', _.before(5, addContactToList));
     * // => allows adding up to 4 contacts to the list
     */
    function before(n, func) {
      var result;
      if (typeof func != 'function') {
        if (typeof n == 'function') {
          var temp = n;
          n = func;
          func = temp;
        } else {
          throw new TypeError(FUNC_ERROR_TEXT);
        }
      }
      return function() {
        if (--n > 0) {
          result = func.apply(this, arguments);
        }
        if (n <= 1) {
          func = null;
        }
        return result;
      };
    }

    /**
     * Creates a function that invokes `func` with the `this` binding of `thisArg`
     * and prepends any additional `_.bind` arguments to those provided to the
     * bound function.
     *
     * The `_.bind.placeholder` value, which defaults to `_` in monolithic builds,
     * may be used as a placeholder for partially applied arguments.
     *
     * **Note:** Unlike native `Function#bind` this method does not set the "length"
     * property of bound functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to bind.
     * @param {*} thisArg The `this` binding of `func`.
     * @param {...*} [partials] The arguments to be partially applied.
     * @returns {Function} Returns the new bound function.
     * @example
     *
     * var greet = function(greeting, punctuation) {
     *   return greeting + ' ' + this.user + punctuation;
     * };
     *
     * var object = { 'user': 'fred' };
     *
     * var bound = _.bind(greet, object, 'hi');
     * bound('!');
     * // => 'hi fred!'
     *
     * // using placeholders
     * var bound = _.bind(greet, object, _, '!');
     * bound('hi');
     * // => 'hi fred!'
     */
    var bind = restParam(function(func, thisArg, partials) {
      var bitmask = BIND_FLAG;
      if (partials.length) {
        var holders = replaceHolders(partials, bind.placeholder);
        bitmask |= PARTIAL_FLAG;
      }
      return createWrapper(func, bitmask, thisArg, partials, holders);
    });

    /**
     * Binds methods of an object to the object itself, overwriting the existing
     * method. Method names may be specified as individual arguments or as arrays
     * of method names. If no method names are provided all enumerable function
     * properties, own and inherited, of `object` are bound.
     *
     * **Note:** This method does not set the "length" property of bound functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Object} object The object to bind and assign the bound methods to.
     * @param {...(string|string[])} [methodNames] The object method names to bind,
     *  specified as individual method names or arrays of method names.
     * @returns {Object} Returns `object`.
     * @example
     *
     * var view = {
     *   'label': 'docs',
     *   'onClick': function() {
     *     console.log('clicked ' + this.label);
     *   }
     * };
     *
     * _.bindAll(view);
     * jQuery('#docs').on('click', view.onClick);
     * // => logs 'clicked docs' when the element is clicked
     */
    var bindAll = restParam(function(object, methodNames) {
      methodNames = methodNames.length ? baseFlatten(methodNames) : functions(object);

      var index = -1,
          length = methodNames.length;

      while (++index < length) {
        var key = methodNames[index];
        object[key] = createWrapper(object[key], BIND_FLAG, object);
      }
      return object;
    });

    /**
     * Creates a function that invokes the method at `object[key]` and prepends
     * any additional `_.bindKey` arguments to those provided to the bound function.
     *
     * This method differs from `_.bind` by allowing bound functions to reference
     * methods that may be redefined or don't yet exist.
     * See [Peter Michaux's article](http://peter.michaux.ca/articles/lazy-function-definition-pattern)
     * for more details.
     *
     * The `_.bindKey.placeholder` value, which defaults to `_` in monolithic
     * builds, may be used as a placeholder for partially applied arguments.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Object} object The object the method belongs to.
     * @param {string} key The key of the method.
     * @param {...*} [partials] The arguments to be partially applied.
     * @returns {Function} Returns the new bound function.
     * @example
     *
     * var object = {
     *   'user': 'fred',
     *   'greet': function(greeting, punctuation) {
     *     return greeting + ' ' + this.user + punctuation;
     *   }
     * };
     *
     * var bound = _.bindKey(object, 'greet', 'hi');
     * bound('!');
     * // => 'hi fred!'
     *
     * object.greet = function(greeting, punctuation) {
     *   return greeting + 'ya ' + this.user + punctuation;
     * };
     *
     * bound('!');
     * // => 'hiya fred!'
     *
     * // using placeholders
     * var bound = _.bindKey(object, 'greet', _, '!');
     * bound('hi');
     * // => 'hiya fred!'
     */
    var bindKey = restParam(function(object, key, partials) {
      var bitmask = BIND_FLAG | BIND_KEY_FLAG;
      if (partials.length) {
        var holders = replaceHolders(partials, bindKey.placeholder);
        bitmask |= PARTIAL_FLAG;
      }
      return createWrapper(key, bitmask, object, partials, holders);
    });

    /**
     * Creates a function that accepts one or more arguments of `func` that when
     * called either invokes `func` returning its result, if all `func` arguments
     * have been provided, or returns a function that accepts one or more of the
     * remaining `func` arguments, and so on. The arity of `func` may be specified
     * if `func.length` is not sufficient.
     *
     * The `_.curry.placeholder` value, which defaults to `_` in monolithic builds,
     * may be used as a placeholder for provided arguments.
     *
     * **Note:** This method does not set the "length" property of curried functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to curry.
     * @param {number} [arity=func.length] The arity of `func`.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Function} Returns the new curried function.
     * @example
     *
     * var abc = function(a, b, c) {
     *   return [a, b, c];
     * };
     *
     * var curried = _.curry(abc);
     *
     * curried(1)(2)(3);
     * // => [1, 2, 3]
     *
     * curried(1, 2)(3);
     * // => [1, 2, 3]
     *
     * curried(1, 2, 3);
     * // => [1, 2, 3]
     *
     * // using placeholders
     * curried(1)(_, 3)(2);
     * // => [1, 2, 3]
     */
    var curry = createCurry(CURRY_FLAG);

    /**
     * This method is like `_.curry` except that arguments are applied to `func`
     * in the manner of `_.partialRight` instead of `_.partial`.
     *
     * The `_.curryRight.placeholder` value, which defaults to `_` in monolithic
     * builds, may be used as a placeholder for provided arguments.
     *
     * **Note:** This method does not set the "length" property of curried functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to curry.
     * @param {number} [arity=func.length] The arity of `func`.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Function} Returns the new curried function.
     * @example
     *
     * var abc = function(a, b, c) {
     *   return [a, b, c];
     * };
     *
     * var curried = _.curryRight(abc);
     *
     * curried(3)(2)(1);
     * // => [1, 2, 3]
     *
     * curried(2, 3)(1);
     * // => [1, 2, 3]
     *
     * curried(1, 2, 3);
     * // => [1, 2, 3]
     *
     * // using placeholders
     * curried(3)(1, _)(2);
     * // => [1, 2, 3]
     */
    var curryRight = createCurry(CURRY_RIGHT_FLAG);

    /**
     * Creates a debounced function that delays invoking `func` until after `wait`
     * milliseconds have elapsed since the last time the debounced function was
     * invoked. The debounced function comes with a `cancel` method to cancel
     * delayed invocations. Provide an options object to indicate that `func`
     * should be invoked on the leading and/or trailing edge of the `wait` timeout.
     * Subsequent calls to the debounced function return the result of the last
     * `func` invocation.
     *
     * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
     * on the trailing edge of the timeout only if the the debounced function is
     * invoked more than once during the `wait` timeout.
     *
     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
     * for details over the differences between `_.debounce` and `_.throttle`.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to debounce.
     * @param {number} [wait=0] The number of milliseconds to delay.
     * @param {Object} [options] The options object.
     * @param {boolean} [options.leading=false] Specify invoking on the leading
     *  edge of the timeout.
     * @param {number} [options.maxWait] The maximum time `func` is allowed to be
     *  delayed before it is invoked.
     * @param {boolean} [options.trailing=true] Specify invoking on the trailing
     *  edge of the timeout.
     * @returns {Function} Returns the new debounced function.
     * @example
     *
     * // avoid costly calculations while the window size is in flux
     * jQuery(window).on('resize', _.debounce(calculateLayout, 150));
     *
     * // invoke `sendMail` when the click event is fired, debouncing subsequent calls
     * jQuery('#postbox').on('click', _.debounce(sendMail, 300, {
     *   'leading': true,
     *   'trailing': false
     * }));
     *
     * // ensure `batchLog` is invoked once after 1 second of debounced calls
     * var source = new EventSource('/stream');
     * jQuery(source).on('message', _.debounce(batchLog, 250, {
     *   'maxWait': 1000
     * }));
     *
     * // cancel a debounced call
     * var todoChanges = _.debounce(batchLog, 1000);
     * Object.observe(models.todo, todoChanges);
     *
     * Object.observe(models, function(changes) {
     *   if (_.find(changes, { 'user': 'todo', 'type': 'delete'})) {
     *     todoChanges.cancel();
     *   }
     * }, ['delete']);
     *
     * // ...at some point `models.todo` is changed
     * models.todo.completed = true;
     *
     * // ...before 1 second has passed `models.todo` is deleted
     * // which cancels the debounced `todoChanges` call
     * delete models.todo;
     */
    function debounce(func, wait, options) {
      var args,
          maxTimeoutId,
          result,
          stamp,
          thisArg,
          timeoutId,
          trailingCall,
          lastCalled = 0,
          maxWait = false,
          trailing = true;

      if (typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      wait = wait < 0 ? 0 : (+wait || 0);
      if (options === true) {
        var leading = true;
        trailing = false;
      } else if (isObject(options)) {
        leading = options.leading;
        maxWait = 'maxWait' in options && nativeMax(+options.maxWait || 0, wait);
        trailing = 'trailing' in options ? options.trailing : trailing;
      }

      function cancel() {
        if (timeoutId) {
          clearTimeout(timeoutId);
        }
        if (maxTimeoutId) {
          clearTimeout(maxTimeoutId);
        }
        maxTimeoutId = timeoutId = trailingCall = undefined;
      }

      function delayed() {
        var remaining = wait - (now() - stamp);
        if (remaining <= 0 || remaining > wait) {
          if (maxTimeoutId) {
            clearTimeout(maxTimeoutId);
          }
          var isCalled = trailingCall;
          maxTimeoutId = timeoutId = trailingCall = undefined;
          if (isCalled) {
            lastCalled = now();
            result = func.apply(thisArg, args);
            if (!timeoutId && !maxTimeoutId) {
              args = thisArg = null;
            }
          }
        } else {
          timeoutId = setTimeout(delayed, remaining);
        }
      }

      function maxDelayed() {
        if (timeoutId) {
          clearTimeout(timeoutId);
        }
        maxTimeoutId = timeoutId = trailingCall = undefined;
        if (trailing || (maxWait !== wait)) {
          lastCalled = now();
          result = func.apply(thisArg, args);
          if (!timeoutId && !maxTimeoutId) {
            args = thisArg = null;
          }
        }
      }

      function debounced() {
        args = arguments;
        stamp = now();
        thisArg = this;
        trailingCall = trailing && (timeoutId || !leading);

        if (maxWait === false) {
          var leadingCall = leading && !timeoutId;
        } else {
          if (!maxTimeoutId && !leading) {
            lastCalled = stamp;
          }
          var remaining = maxWait - (stamp - lastCalled),
              isCalled = remaining <= 0 || remaining > maxWait;

          if (isCalled) {
            if (maxTimeoutId) {
              maxTimeoutId = clearTimeout(maxTimeoutId);
            }
            lastCalled = stamp;
            result = func.apply(thisArg, args);
          }
          else if (!maxTimeoutId) {
            maxTimeoutId = setTimeout(maxDelayed, remaining);
          }
        }
        if (isCalled && timeoutId) {
          timeoutId = clearTimeout(timeoutId);
        }
        else if (!timeoutId && wait !== maxWait) {
          timeoutId = setTimeout(delayed, wait);
        }
        if (leadingCall) {
          isCalled = true;
          result = func.apply(thisArg, args);
        }
        if (isCalled && !timeoutId && !maxTimeoutId) {
          args = thisArg = null;
        }
        return result;
      }
      debounced.cancel = cancel;
      return debounced;
    }

    /**
     * Defers invoking the `func` until the current call stack has cleared. Any
     * additional arguments are provided to `func` when it is invoked.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to defer.
     * @param {...*} [args] The arguments to invoke the function with.
     * @returns {number} Returns the timer id.
     * @example
     *
     * _.defer(function(text) {
     *   console.log(text);
     * }, 'deferred');
     * // logs 'deferred' after one or more milliseconds
     */
    var defer = restParam(function(func, args) {
      return baseDelay(func, 1, args);
    });

    /**
     * Invokes `func` after `wait` milliseconds. Any additional arguments are
     * provided to `func` when it is invoked.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to delay.
     * @param {number} wait The number of milliseconds to delay invocation.
     * @param {...*} [args] The arguments to invoke the function with.
     * @returns {number} Returns the timer id.
     * @example
     *
     * _.delay(function(text) {
     *   console.log(text);
     * }, 1000, 'later');
     * // => logs 'later' after one second
     */
    var delay = restParam(function(func, wait, args) {
      return baseDelay(func, wait, args);
    });

    /**
     * Creates a function that returns the result of invoking the provided
     * functions with the `this` binding of the created function, where each
     * successive invocation is supplied the return value of the previous.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {...Function} [funcs] Functions to invoke.
     * @returns {Function} Returns the new function.
     * @example
     *
     * function square(n) {
     *   return n * n;
     * }
     *
     * var addSquare = _.flow(_.add, square);
     * addSquare(1, 2);
     * // => 9
     */
    var flow = createFlow();

    /**
     * This method is like `_.flow` except that it creates a function that
     * invokes the provided functions from right to left.
     *
     * @static
     * @memberOf _
     * @alias backflow, compose
     * @category Function
     * @param {...Function} [funcs] Functions to invoke.
     * @returns {Function} Returns the new function.
     * @example
     *
     * function square(n) {
     *   return n * n;
     * }
     *
     * var addSquare = _.flowRight(square, _.add);
     * addSquare(1, 2);
     * // => 9
     */
    var flowRight = createFlow(true);

    /**
     * Creates a function that memoizes the result of `func`. If `resolver` is
     * provided it determines the cache key for storing the result based on the
     * arguments provided to the memoized function. By default, the first argument
     * provided to the memoized function is coerced to a string and used as the
     * cache key. The `func` is invoked with the `this` binding of the memoized
     * function.
     *
     * **Note:** The cache is exposed as the `cache` property on the memoized
     * function. Its creation may be customized by replacing the `_.memoize.Cache`
     * constructor with one whose instances implement the [`Map`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-properties-of-the-map-prototype-object)
     * method interface of `get`, `has`, and `set`.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to have its output memoized.
     * @param {Function} [resolver] The function to resolve the cache key.
     * @returns {Function} Returns the new memoizing function.
     * @example
     *
     * var upperCase = _.memoize(function(string) {
     *   return string.toUpperCase();
     * });
     *
     * upperCase('fred');
     * // => 'FRED'
     *
     * // modifying the result cache
     * upperCase.cache.set('fred', 'BARNEY');
     * upperCase('fred');
     * // => 'BARNEY'
     *
     * // replacing `_.memoize.Cache`
     * var object = { 'user': 'fred' };
     * var other = { 'user': 'barney' };
     * var identity = _.memoize(_.identity);
     *
     * identity(object);
     * // => { 'user': 'fred' }
     * identity(other);
     * // => { 'user': 'fred' }
     *
     * _.memoize.Cache = WeakMap;
     * var identity = _.memoize(_.identity);
     *
     * identity(object);
     * // => { 'user': 'fred' }
     * identity(other);
     * // => { 'user': 'barney' }
     */
    function memoize(func, resolver) {
      if (typeof func != 'function' || (resolver && typeof resolver != 'function')) {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      var memoized = function() {
        var args = arguments,
            key = resolver ? resolver.apply(this, args) : args[0],
            cache = memoized.cache;

        if (cache.has(key)) {
          return cache.get(key);
        }
        var result = func.apply(this, args);
        memoized.cache = cache.set(key, result);
        return result;
      };
      memoized.cache = new memoize.Cache;
      return memoized;
    }

    /**
     * Creates a function that negates the result of the predicate `func`. The
     * `func` predicate is invoked with the `this` binding and arguments of the
     * created function.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} predicate The predicate to negate.
     * @returns {Function} Returns the new function.
     * @example
     *
     * function isEven(n) {
     *   return n % 2 == 0;
     * }
     *
     * _.filter([1, 2, 3, 4, 5, 6], _.negate(isEven));
     * // => [1, 3, 5]
     */
    function negate(predicate) {
      if (typeof predicate != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      return function() {
        return !predicate.apply(this, arguments);
      };
    }

    /**
     * Creates a function that is restricted to invoking `func` once. Repeat calls
     * to the function return the value of the first call. The `func` is invoked
     * with the `this` binding and arguments of the created function.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to restrict.
     * @returns {Function} Returns the new restricted function.
     * @example
     *
     * var initialize = _.once(createApplication);
     * initialize();
     * initialize();
     * // `initialize` invokes `createApplication` once
     */
    function once(func) {
      return before(2, func);
    }

    /**
     * Creates a function that invokes `func` with `partial` arguments prepended
     * to those provided to the new function. This method is like `_.bind` except
     * it does **not** alter the `this` binding.
     *
     * The `_.partial.placeholder` value, which defaults to `_` in monolithic
     * builds, may be used as a placeholder for partially applied arguments.
     *
     * **Note:** This method does not set the "length" property of partially
     * applied functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to partially apply arguments to.
     * @param {...*} [partials] The arguments to be partially applied.
     * @returns {Function} Returns the new partially applied function.
     * @example
     *
     * var greet = function(greeting, name) {
     *   return greeting + ' ' + name;
     * };
     *
     * var sayHelloTo = _.partial(greet, 'hello');
     * sayHelloTo('fred');
     * // => 'hello fred'
     *
     * // using placeholders
     * var greetFred = _.partial(greet, _, 'fred');
     * greetFred('hi');
     * // => 'hi fred'
     */
    var partial = createPartial(PARTIAL_FLAG);

    /**
     * This method is like `_.partial` except that partially applied arguments
     * are appended to those provided to the new function.
     *
     * The `_.partialRight.placeholder` value, which defaults to `_` in monolithic
     * builds, may be used as a placeholder for partially applied arguments.
     *
     * **Note:** This method does not set the "length" property of partially
     * applied functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to partially apply arguments to.
     * @param {...*} [partials] The arguments to be partially applied.
     * @returns {Function} Returns the new partially applied function.
     * @example
     *
     * var greet = function(greeting, name) {
     *   return greeting + ' ' + name;
     * };
     *
     * var greetFred = _.partialRight(greet, 'fred');
     * greetFred('hi');
     * // => 'hi fred'
     *
     * // using placeholders
     * var sayHelloTo = _.partialRight(greet, 'hello', _);
     * sayHelloTo('fred');
     * // => 'hello fred'
     */
    var partialRight = createPartial(PARTIAL_RIGHT_FLAG);

    /**
     * Creates a function that invokes `func` with arguments arranged according
     * to the specified indexes where the argument value at the first index is
     * provided as the first argument, the argument value at the second index is
     * provided as the second argument, and so on.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to rearrange arguments for.
     * @param {...(number|number[])} indexes The arranged argument indexes,
     *  specified as individual indexes or arrays of indexes.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var rearged = _.rearg(function(a, b, c) {
     *   return [a, b, c];
     * }, 2, 0, 1);
     *
     * rearged('b', 'c', 'a')
     * // => ['a', 'b', 'c']
     *
     * var map = _.rearg(_.map, [1, 0]);
     * map(function(n) {
     *   return n * 3;
     * }, [1, 2, 3]);
     * // => [3, 6, 9]
     */
    var rearg = restParam(function(func, indexes) {
      return createWrapper(func, REARG_FLAG, null, null, null, baseFlatten(indexes));
    });

    /**
     * Creates a function that invokes `func` with the `this` binding of the
     * created function and arguments from `start` and beyond provided as an array.
     *
     * **Note:** This method is based on the [rest parameter](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters).
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to apply a rest parameter to.
     * @param {number} [start=func.length-1] The start position of the rest parameter.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var say = _.restParam(function(what, names) {
     *   return what + ' ' + _.initial(names).join(', ') +
     *     (_.size(names) > 1 ? ', & ' : '') + _.last(names);
     * });
     *
     * say('hello', 'fred', 'barney', 'pebbles');
     * // => 'hello fred, barney, & pebbles'
     */
    function restParam(func, start) {
      if (typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      start = nativeMax(start === undefined ? (func.length - 1) : (+start || 0), 0);
      return function() {
        var args = arguments,
            index = -1,
            length = nativeMax(args.length - start, 0),
            rest = Array(length);

        while (++index < length) {
          rest[index] = args[start + index];
        }
        switch (start) {
          case 0: return func.call(this, rest);
          case 1: return func.call(this, args[0], rest);
          case 2: return func.call(this, args[0], args[1], rest);
        }
        var otherArgs = Array(start + 1);
        index = -1;
        while (++index < start) {
          otherArgs[index] = args[index];
        }
        otherArgs[start] = rest;
        return func.apply(this, otherArgs);
      };
    }

    /**
     * Creates a function that invokes `func` with the `this` binding of the created
     * function and an array of arguments much like [`Function#apply`](https://es5.github.io/#x15.3.4.3).
     *
     * **Note:** This method is based on the [spread operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator).
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to spread arguments over.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var say = _.spread(function(who, what) {
     *   return who + ' says ' + what;
     * });
     *
     * say(['fred', 'hello']);
     * // => 'fred says hello'
     *
     * // with a Promise
     * var numbers = Promise.all([
     *   Promise.resolve(40),
     *   Promise.resolve(36)
     * ]);
     *
     * numbers.then(_.spread(function(x, y) {
     *   return x + y;
     * }));
     * // => a Promise of 76
     */
    function spread(func) {
      if (typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      return function(array) {
        return func.apply(this, array);
      };
    }

    /**
     * Creates a throttled function that only invokes `func` at most once per
     * every `wait` milliseconds. The throttled function comes with a `cancel`
     * method to cancel delayed invocations. Provide an options object to indicate
     * that `func` should be invoked on the leading and/or trailing edge of the
     * `wait` timeout. Subsequent calls to the throttled function return the
     * result of the last `func` call.
     *
     * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
     * on the trailing edge of the timeout only if the the throttled function is
     * invoked more than once during the `wait` timeout.
     *
     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
     * for details over the differences between `_.throttle` and `_.debounce`.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to throttle.
     * @param {number} [wait=0] The number of milliseconds to throttle invocations to.
     * @param {Object} [options] The options object.
     * @param {boolean} [options.leading=true] Specify invoking on the leading
     *  edge of the timeout.
     * @param {boolean} [options.trailing=true] Specify invoking on the trailing
     *  edge of the timeout.
     * @returns {Function} Returns the new throttled function.
     * @example
     *
     * // avoid excessively updating the position while scrolling
     * jQuery(window).on('scroll', _.throttle(updatePosition, 100));
     *
     * // invoke `renewToken` when the click event is fired, but not more than once every 5 minutes
     * jQuery('.interactive').on('click', _.throttle(renewToken, 300000, {
     *   'trailing': false
     * }));
     *
     * // cancel a trailing throttled call
     * jQuery(window).on('popstate', throttled.cancel);
     */
    function throttle(func, wait, options) {
      var leading = true,
          trailing = true;

      if (typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      if (options === false) {
        leading = false;
      } else if (isObject(options)) {
        leading = 'leading' in options ? !!options.leading : leading;
        trailing = 'trailing' in options ? !!options.trailing : trailing;
      }
      debounceOptions.leading = leading;
      debounceOptions.maxWait = +wait;
      debounceOptions.trailing = trailing;
      return debounce(func, wait, debounceOptions);
    }

    /**
     * Creates a function that provides `value` to the wrapper function as its
     * first argument. Any additional arguments provided to the function are
     * appended to those provided to the wrapper function. The wrapper is invoked
     * with the `this` binding of the created function.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {*} value The value to wrap.
     * @param {Function} wrapper The wrapper function.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var p = _.wrap(_.escape, function(func, text) {
     *   return '<p>' + func(text) + '</p>';
     * });
     *
     * p('fred, barney, & pebbles');
     * // => '<p>fred, barney, &amp; pebbles</p>'
     */
    function wrap(value, wrapper) {
      wrapper = wrapper == null ? identity : wrapper;
      return createWrapper(wrapper, PARTIAL_FLAG, null, [value], []);
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates a clone of `value`. If `isDeep` is `true` nested objects are cloned,
     * otherwise they are assigned by reference. If `customizer` is provided it is
     * invoked to produce the cloned values. If `customizer` returns `undefined`
     * cloning is handled by the method instead. The `customizer` is bound to
     * `thisArg` and invoked with two argument; (value [, index|key, object]).
     *
     * **Note:** This method is loosely based on the
     * [structured clone algorithm](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm).
     * The enumerable properties of `arguments` objects and objects created by
     * constructors other than `Object` are cloned to plain `Object` objects. An
     * empty object is returned for uncloneable values such as functions, DOM nodes,
     * Maps, Sets, and WeakMaps.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to clone.
     * @param {boolean} [isDeep] Specify a deep clone.
     * @param {Function} [customizer] The function to customize cloning values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {*} Returns the cloned value.
     * @example
     *
     * var users = [
     *   { 'user': 'barney' },
     *   { 'user': 'fred' }
     * ];
     *
     * var shallow = _.clone(users);
     * shallow[0] === users[0];
     * // => true
     *
     * var deep = _.clone(users, true);
     * deep[0] === users[0];
     * // => false
     *
     * // using a customizer callback
     * var el = _.clone(document.body, function(value) {
     *   if (_.isElement(value)) {
     *     return value.cloneNode(false);
     *   }
     * });
     *
     * el === document.body
     * // => false
     * el.nodeName
     * // => BODY
     * el.childNodes.length;
     * // => 0
     */
    function clone(value, isDeep, customizer, thisArg) {
      if (isDeep && typeof isDeep != 'boolean' && isIterateeCall(value, isDeep, customizer)) {
        isDeep = false;
      }
      else if (typeof isDeep == 'function') {
        thisArg = customizer;
        customizer = isDeep;
        isDeep = false;
      }
      return typeof customizer == 'function'
        ? baseClone(value, isDeep, bindCallback(customizer, thisArg, 1))
        : baseClone(value, isDeep);
    }

    /**
     * Creates a deep clone of `value`. If `customizer` is provided it is invoked
     * to produce the cloned values. If `customizer` returns `undefined` cloning
     * is handled by the method instead. The `customizer` is bound to `thisArg`
     * and invoked with two argument; (value [, index|key, object]).
     *
     * **Note:** This method is loosely based on the
     * [structured clone algorithm](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm).
     * The enumerable properties of `arguments` objects and objects created by
     * constructors other than `Object` are cloned to plain `Object` objects. An
     * empty object is returned for uncloneable values such as functions, DOM nodes,
     * Maps, Sets, and WeakMaps.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to deep clone.
     * @param {Function} [customizer] The function to customize cloning values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {*} Returns the deep cloned value.
     * @example
     *
     * var users = [
     *   { 'user': 'barney' },
     *   { 'user': 'fred' }
     * ];
     *
     * var deep = _.cloneDeep(users);
     * deep[0] === users[0];
     * // => false
     *
     * // using a customizer callback
     * var el = _.cloneDeep(document.body, function(value) {
     *   if (_.isElement(value)) {
     *     return value.cloneNode(true);
     *   }
     * });
     *
     * el === document.body
     * // => false
     * el.nodeName
     * // => BODY
     * el.childNodes.length;
     * // => 20
     */
    function cloneDeep(value, customizer, thisArg) {
      return typeof customizer == 'function'
        ? baseClone(value, true, bindCallback(customizer, thisArg, 1))
        : baseClone(value, true);
    }

    /**
     * Checks if `value` is greater than `other`.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to compare.
     * @param {*} other The other value to compare.
     * @returns {boolean} Returns `true` if `value` is greater than `other`, else `false`.
     * @example
     *
     * _.gt(3, 1);
     * // => true
     *
     * _.gt(3, 3);
     * // => false
     *
     * _.gt(1, 3);
     * // => false
     */
    function gt(value, other) {
      return value > other;
    }

    /**
     * Checks if `value` is greater than or equal to `other`.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to compare.
     * @param {*} other The other value to compare.
     * @returns {boolean} Returns `true` if `value` is greater than or equal to `other`, else `false`.
     * @example
     *
     * _.gte(3, 1);
     * // => true
     *
     * _.gte(3, 3);
     * // => true
     *
     * _.gte(1, 3);
     * // => false
     */
    function gte(value, other) {
      return value >= other;
    }

    /**
     * Checks if `value` is classified as an `arguments` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isArguments(function() { return arguments; }());
     * // => true
     *
     * _.isArguments([1, 2, 3]);
     * // => false
     */
    function isArguments(value) {
      return isObjectLike(value) && isArrayLike(value) && objToString.call(value) == argsTag;
    }

    /**
     * Checks if `value` is classified as an `Array` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isArray([1, 2, 3]);
     * // => true
     *
     * _.isArray(function() { return arguments; }());
     * // => false
     */
    var isArray = nativeIsArray || function(value) {
      return isObjectLike(value) && isLength(value.length) && objToString.call(value) == arrayTag;
    };

    /**
     * Checks if `value` is classified as a boolean primitive or object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isBoolean(false);
     * // => true
     *
     * _.isBoolean(null);
     * // => false
     */
    function isBoolean(value) {
      return value === true || value === false || (isObjectLike(value) && objToString.call(value) == boolTag);
    }

    /**
     * Checks if `value` is classified as a `Date` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isDate(new Date);
     * // => true
     *
     * _.isDate('Mon April 23 2012');
     * // => false
     */
    function isDate(value) {
      return isObjectLike(value) && objToString.call(value) == dateTag;
    }

    /**
     * Checks if `value` is a DOM element.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a DOM element, else `false`.
     * @example
     *
     * _.isElement(document.body);
     * // => true
     *
     * _.isElement('<body>');
     * // => false
     */
    function isElement(value) {
      return !!value && value.nodeType === 1 && isObjectLike(value) &&
        (objToString.call(value).indexOf('Element') > -1);
    }
    // Fallback for environments without DOM support.
    if (!support.dom) {
      isElement = function(value) {
        return !!value && value.nodeType === 1 && isObjectLike(value) && !isPlainObject(value);
      };
    }

    /**
     * Checks if `value` is empty. A value is considered empty unless it is an
     * `arguments` object, array, string, or jQuery-like collection with a length
     * greater than `0` or an object with own enumerable properties.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {Array|Object|string} value The value to inspect.
     * @returns {boolean} Returns `true` if `value` is empty, else `false`.
     * @example
     *
     * _.isEmpty(null);
     * // => true
     *
     * _.isEmpty(true);
     * // => true
     *
     * _.isEmpty(1);
     * // => true
     *
     * _.isEmpty([1, 2, 3]);
     * // => false
     *
     * _.isEmpty({ 'a': 1 });
     * // => false
     */
    function isEmpty(value) {
      if (value == null) {
        return true;
      }
      if (isArrayLike(value) && (isArray(value) || isString(value) || isArguments(value) ||
          (isObjectLike(value) && isFunction(value.splice)))) {
        return !value.length;
      }
      return !keys(value).length;
    }

    /**
     * Performs a deep comparison between two values to determine if they are
     * equivalent. If `customizer` is provided it is invoked to compare values.
     * If `customizer` returns `undefined` comparisons are handled by the method
     * instead. The `customizer` is bound to `thisArg` and invoked with three
     * arguments: (value, other [, index|key]).
     *
     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
     * numbers, `Object` objects, regexes, and strings. Objects are compared by
     * their own, not inherited, enumerable properties. Functions and DOM nodes
     * are **not** supported. Provide a customizer function to extend support
     * for comparing other values.
     *
     * @static
     * @memberOf _
     * @alias eq
     * @category Lang
     * @param {*} value The value to compare.
     * @param {*} other The other value to compare.
     * @param {Function} [customizer] The function to customize value comparisons.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
     * @example
     *
     * var object = { 'user': 'fred' };
     * var other = { 'user': 'fred' };
     *
     * object == other;
     * // => false
     *
     * _.isEqual(object, other);
     * // => true
     *
     * // using a customizer callback
     * var array = ['hello', 'goodbye'];
     * var other = ['hi', 'goodbye'];
     *
     * _.isEqual(array, other, function(value, other) {
     *   if (_.every([value, other], RegExp.prototype.test, /^h(?:i|ello)$/)) {
     *     return true;
     *   }
     * });
     * // => true
     */
    function isEqual(value, other, customizer, thisArg) {
      customizer = typeof customizer == 'function' ? bindCallback(customizer, thisArg, 3) : undefined;
      var result = customizer ? customizer(value, other) : undefined;
      return  result === undefined ? baseIsEqual(value, other, customizer) : !!result;
    }

    /**
     * Checks if `value` is an `Error`, `EvalError`, `RangeError`, `ReferenceError`,
     * `SyntaxError`, `TypeError`, or `URIError` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is an error object, else `false`.
     * @example
     *
     * _.isError(new Error);
     * // => true
     *
     * _.isError(Error);
     * // => false
     */
    function isError(value) {
      return isObjectLike(value) && typeof value.message == 'string' && objToString.call(value) == errorTag;
    }

    /**
     * Checks if `value` is a finite primitive number.
     *
     * **Note:** This method is based on [`Number.isFinite`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.isfinite).
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a finite number, else `false`.
     * @example
     *
     * _.isFinite(10);
     * // => true
     *
     * _.isFinite('10');
     * // => false
     *
     * _.isFinite(true);
     * // => false
     *
     * _.isFinite(Object(10));
     * // => false
     *
     * _.isFinite(Infinity);
     * // => false
     */
    var isFinite = nativeNumIsFinite || function(value) {
      return typeof value == 'number' && nativeIsFinite(value);
    };

    /**
     * Checks if `value` is classified as a `Function` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isFunction(_);
     * // => true
     *
     * _.isFunction(/abc/);
     * // => false
     */
    var isFunction = !(baseIsFunction(/x/) || (Uint8Array && !baseIsFunction(Uint8Array))) ? baseIsFunction : function(value) {
      // The use of `Object#toString` avoids issues with the `typeof` operator
      // in older versions of Chrome and Safari which return 'function' for regexes
      // and Safari 8 equivalents which return 'object' for typed array constructors.
      return objToString.call(value) == funcTag;
    };

    /**
     * Checks if `value` is the [language type](https://es5.github.io/#x8) of `Object`.
     * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is an object, else `false`.
     * @example
     *
     * _.isObject({});
     * // => true
     *
     * _.isObject([1, 2, 3]);
     * // => true
     *
     * _.isObject(1);
     * // => false
     */
    function isObject(value) {
      // Avoid a V8 JIT bug in Chrome 19-20.
      // See https://code.google.com/p/v8/issues/detail?id=2291 for more details.
      var type = typeof value;
      return !!value && (type == 'object' || type == 'function');
    }

    /**
     * Performs a deep comparison between `object` and `source` to determine if
     * `object` contains equivalent property values. If `customizer` is provided
     * it is invoked to compare values. If `customizer` returns `undefined`
     * comparisons are handled by the method instead. The `customizer` is bound
     * to `thisArg` and invoked with three arguments: (value, other, index|key).
     *
     * **Note:** This method supports comparing properties of arrays, booleans,
     * `Date` objects, numbers, `Object` objects, regexes, and strings. Functions
     * and DOM nodes are **not** supported. Provide a customizer function to extend
     * support for comparing other values.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {Object} object The object to inspect.
     * @param {Object} source The object of property values to match.
     * @param {Function} [customizer] The function to customize value comparisons.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {boolean} Returns `true` if `object` is a match, else `false`.
     * @example
     *
     * var object = { 'user': 'fred', 'age': 40 };
     *
     * _.isMatch(object, { 'age': 40 });
     * // => true
     *
     * _.isMatch(object, { 'age': 36 });
     * // => false
     *
     * // using a customizer callback
     * var object = { 'greeting': 'hello' };
     * var source = { 'greeting': 'hi' };
     *
     * _.isMatch(object, source, function(value, other) {
     *   return _.every([value, other], RegExp.prototype.test, /^h(?:i|ello)$/) || undefined;
     * });
     * // => true
     */
    function isMatch(object, source, customizer, thisArg) {
      customizer = typeof customizer == 'function' ? bindCallback(customizer, thisArg, 3) : undefined;
      return baseIsMatch(object, getMatchData(source), customizer);
    }

    /**
     * Checks if `value` is `NaN`.
     *
     * **Note:** This method is not the same as [`isNaN`](https://es5.github.io/#x15.1.2.4)
     * which returns `true` for `undefined` and other non-numeric values.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.
     * @example
     *
     * _.isNaN(NaN);
     * // => true
     *
     * _.isNaN(new Number(NaN));
     * // => true
     *
     * isNaN(undefined);
     * // => true
     *
     * _.isNaN(undefined);
     * // => false
     */
    function isNaN(value) {
      // An `NaN` primitive is the only value that is not equal to itself.
      // Perform the `toStringTag` check first to avoid errors with some host objects in IE.
      return isNumber(value) && value != +value;
    }

    /**
     * Checks if `value` is a native function.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a native function, else `false`.
     * @example
     *
     * _.isNative(Array.prototype.push);
     * // => true
     *
     * _.isNative(_);
     * // => false
     */
    function isNative(value) {
      if (value == null) {
        return false;
      }
      if (objToString.call(value) == funcTag) {
        return reIsNative.test(fnToString.call(value));
      }
      return isObjectLike(value) && reIsHostCtor.test(value);
    }

    /**
     * Checks if `value` is `null`.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is `null`, else `false`.
     * @example
     *
     * _.isNull(null);
     * // => true
     *
     * _.isNull(void 0);
     * // => false
     */
    function isNull(value) {
      return value === null;
    }

    /**
     * Checks if `value` is classified as a `Number` primitive or object.
     *
     * **Note:** To exclude `Infinity`, `-Infinity`, and `NaN`, which are classified
     * as numbers, use the `_.isFinite` method.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isNumber(8.4);
     * // => true
     *
     * _.isNumber(NaN);
     * // => true
     *
     * _.isNumber('8.4');
     * // => false
     */
    function isNumber(value) {
      return typeof value == 'number' || (isObjectLike(value) && objToString.call(value) == numberTag);
    }

    /**
     * Checks if `value` is a plain object, that is, an object created by the
     * `Object` constructor or one with a `[[Prototype]]` of `null`.
     *
     * **Note:** This method assumes objects created by the `Object` constructor
     * have no inherited enumerable properties.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     * }
     *
     * _.isPlainObject(new Foo);
     * // => false
     *
     * _.isPlainObject([1, 2, 3]);
     * // => false
     *
     * _.isPlainObject({ 'x': 0, 'y': 0 });
     * // => true
     *
     * _.isPlainObject(Object.create(null));
     * // => true
     */
    var isPlainObject = !getPrototypeOf ? shimIsPlainObject : function(value) {
      if (!(value && objToString.call(value) == objectTag)) {
        return false;
      }
      var valueOf = getNative(value, 'valueOf'),
          objProto = valueOf && (objProto = getPrototypeOf(valueOf)) && getPrototypeOf(objProto);

      return objProto
        ? (value == objProto || getPrototypeOf(value) == objProto)
        : shimIsPlainObject(value);
    };

    /**
     * Checks if `value` is classified as a `RegExp` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isRegExp(/abc/);
     * // => true
     *
     * _.isRegExp('/abc/');
     * // => false
     */
    function isRegExp(value) {
      return isObjectLike(value) && objToString.call(value) == regexpTag;
    }

    /**
     * Checks if `value` is classified as a `String` primitive or object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isString('abc');
     * // => true
     *
     * _.isString(1);
     * // => false
     */
    function isString(value) {
      return typeof value == 'string' || (isObjectLike(value) && objToString.call(value) == stringTag);
    }

    /**
     * Checks if `value` is classified as a typed array.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isTypedArray(new Uint8Array);
     * // => true
     *
     * _.isTypedArray([]);
     * // => false
     */
    function isTypedArray(value) {
      return isObjectLike(value) && isLength(value.length) && !!typedArrayTags[objToString.call(value)];
    }

    /**
     * Checks if `value` is `undefined`.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is `undefined`, else `false`.
     * @example
     *
     * _.isUndefined(void 0);
     * // => true
     *
     * _.isUndefined(null);
     * // => false
     */
    function isUndefined(value) {
      return value === undefined;
    }

    /**
     * Checks if `value` is less than `other`.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to compare.
     * @param {*} other The other value to compare.
     * @returns {boolean} Returns `true` if `value` is less than `other`, else `false`.
     * @example
     *
     * _.lt(1, 3);
     * // => true
     *
     * _.lt(3, 3);
     * // => false
     *
     * _.lt(3, 1);
     * // => false
     */
    function lt(value, other) {
      return value < other;
    }

    /**
     * Checks if `value` is less than or equal to `other`.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to compare.
     * @param {*} other The other value to compare.
     * @returns {boolean} Returns `true` if `value` is less than or equal to `other`, else `false`.
     * @example
     *
     * _.lte(1, 3);
     * // => true
     *
     * _.lte(3, 3);
     * // => true
     *
     * _.lte(3, 1);
     * // => false
     */
    function lte(value, other) {
      return value <= other;
    }

    /**
     * Converts `value` to an array.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to convert.
     * @returns {Array} Returns the converted array.
     * @example
     *
     * (function() {
     *   return _.toArray(arguments).slice(1);
     * }(1, 2, 3));
     * // => [2, 3]
     */
    function toArray(value) {
      var length = value ? getLength(value) : 0;
      if (!isLength(length)) {
        return values(value);
      }
      if (!length) {
        return [];
      }
      return arrayCopy(value);
    }

    /**
     * Converts `value` to a plain object flattening inherited enumerable
     * properties of `value` to own properties of the plain object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to convert.
     * @returns {Object} Returns the converted plain object.
     * @example
     *
     * function Foo() {
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.assign({ 'a': 1 }, new Foo);
     * // => { 'a': 1, 'b': 2 }
     *
     * _.assign({ 'a': 1 }, _.toPlainObject(new Foo));
     * // => { 'a': 1, 'b': 2, 'c': 3 }
     */
    function toPlainObject(value) {
      return baseCopy(value, keysIn(value));
    }

    /*------------------------------------------------------------------------*/

    /**
     * Assigns own enumerable properties of source object(s) to the destination
     * object. Subsequent sources overwrite property assignments of previous sources.
     * If `customizer` is provided it is invoked to produce the assigned values.
     * The `customizer` is bound to `thisArg` and invoked with five arguments:
     * (objectValue, sourceValue, key, object, source).
     *
     * **Note:** This method mutates `object` and is based on
     * [`Object.assign`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.assign).
     *
     * @static
     * @memberOf _
     * @alias extend
     * @category Object
     * @param {Object} object The destination object.
     * @param {...Object} [sources] The source objects.
     * @param {Function} [customizer] The function to customize assigned values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * _.assign({ 'user': 'barney' }, { 'age': 40 }, { 'user': 'fred' });
     * // => { 'user': 'fred', 'age': 40 }
     *
     * // using a customizer callback
     * var defaults = _.partialRight(_.assign, function(value, other) {
     *   return _.isUndefined(value) ? other : value;
     * });
     *
     * defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred' });
     * // => { 'user': 'barney', 'age': 36 }
     */
    var assign = createAssigner(function(object, source, customizer) {
      return customizer
        ? assignWith(object, source, customizer)
        : baseAssign(object, source);
    });

    /**
     * Creates an object that inherits from the given `prototype` object. If a
     * `properties` object is provided its own enumerable properties are assigned
     * to the created object.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} prototype The object to inherit from.
     * @param {Object} [properties] The properties to assign to the object.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Object} Returns the new object.
     * @example
     *
     * function Shape() {
     *   this.x = 0;
     *   this.y = 0;
     * }
     *
     * function Circle() {
     *   Shape.call(this);
     * }
     *
     * Circle.prototype = _.create(Shape.prototype, {
     *   'constructor': Circle
     * });
     *
     * var circle = new Circle;
     * circle instanceof Circle;
     * // => true
     *
     * circle instanceof Shape;
     * // => true
     */
    function create(prototype, properties, guard) {
      var result = baseCreate(prototype);
      if (guard && isIterateeCall(prototype, properties, guard)) {
        properties = null;
      }
      return properties ? baseAssign(result, properties) : result;
    }

    /**
     * Assigns own enumerable properties of source object(s) to the destination
     * object for all destination properties that resolve to `undefined`. Once a
     * property is set, additional values of the same property are ignored.
     *
     * **Note:** This method mutates `object`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The destination object.
     * @param {...Object} [sources] The source objects.
     * @returns {Object} Returns `object`.
     * @example
     *
     * _.defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred' });
     * // => { 'user': 'barney', 'age': 36 }
     */
    var defaults = restParam(function(args) {
      var object = args[0];
      if (object == null) {
        return object;
      }
      args.push(assignDefaults);
      return assign.apply(undefined, args);
    });

    /**
     * This method is like `_.find` except that it returns the key of the first
     * element `predicate` returns truthy for instead of the element itself.
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {string|undefined} Returns the key of the matched element, else `undefined`.
     * @example
     *
     * var users = {
     *   'barney':  { 'age': 36, 'active': true },
     *   'fred':    { 'age': 40, 'active': false },
     *   'pebbles': { 'age': 1,  'active': true }
     * };
     *
     * _.findKey(users, function(chr) {
     *   return chr.age < 40;
     * });
     * // => 'barney' (iteration order is not guaranteed)
     *
     * // using the `_.matches` callback shorthand
     * _.findKey(users, { 'age': 1, 'active': true });
     * // => 'pebbles'
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.findKey(users, 'active', false);
     * // => 'fred'
     *
     * // using the `_.property` callback shorthand
     * _.findKey(users, 'active');
     * // => 'barney'
     */
    var findKey = createFindKey(baseForOwn);

    /**
     * This method is like `_.findKey` except that it iterates over elements of
     * a collection in the opposite order.
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {string|undefined} Returns the key of the matched element, else `undefined`.
     * @example
     *
     * var users = {
     *   'barney':  { 'age': 36, 'active': true },
     *   'fred':    { 'age': 40, 'active': false },
     *   'pebbles': { 'age': 1,  'active': true }
     * };
     *
     * _.findLastKey(users, function(chr) {
     *   return chr.age < 40;
     * });
     * // => returns `pebbles` assuming `_.findKey` returns `barney`
     *
     * // using the `_.matches` callback shorthand
     * _.findLastKey(users, { 'age': 36, 'active': true });
     * // => 'barney'
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.findLastKey(users, 'active', false);
     * // => 'fred'
     *
     * // using the `_.property` callback shorthand
     * _.findLastKey(users, 'active');
     * // => 'pebbles'
     */
    var findLastKey = createFindKey(baseForOwnRight);

    /**
     * Iterates over own and inherited enumerable properties of an object invoking
     * `iteratee` for each property. The `iteratee` is bound to `thisArg` and invoked
     * with three arguments: (value, key, object). Iteratee functions may exit
     * iteration early by explicitly returning `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.forIn(new Foo, function(value, key) {
     *   console.log(key);
     * });
     * // => logs 'a', 'b', and 'c' (iteration order is not guaranteed)
     */
    var forIn = createForIn(baseFor);

    /**
     * This method is like `_.forIn` except that it iterates over properties of
     * `object` in the opposite order.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.forInRight(new Foo, function(value, key) {
     *   console.log(key);
     * });
     * // => logs 'c', 'b', and 'a' assuming `_.forIn ` logs 'a', 'b', and 'c'
     */
    var forInRight = createForIn(baseForRight);

    /**
     * Iterates over own enumerable properties of an object invoking `iteratee`
     * for each property. The `iteratee` is bound to `thisArg` and invoked with
     * three arguments: (value, key, object). Iteratee functions may exit iteration
     * early by explicitly returning `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.forOwn(new Foo, function(value, key) {
     *   console.log(key);
     * });
     * // => logs 'a' and 'b' (iteration order is not guaranteed)
     */
    var forOwn = createForOwn(baseForOwn);

    /**
     * This method is like `_.forOwn` except that it iterates over properties of
     * `object` in the opposite order.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.forOwnRight(new Foo, function(value, key) {
     *   console.log(key);
     * });
     * // => logs 'b' and 'a' assuming `_.forOwn` logs 'a' and 'b'
     */
    var forOwnRight = createForOwn(baseForOwnRight);

    /**
     * Creates an array of function property names from all enumerable properties,
     * own and inherited, of `object`.
     *
     * @static
     * @memberOf _
     * @alias methods
     * @category Object
     * @param {Object} object The object to inspect.
     * @returns {Array} Returns the new array of property names.
     * @example
     *
     * _.functions(_);
     * // => ['after', 'ary', 'assign', ...]
     */
    function functions(object) {
      return baseFunctions(object, keysIn(object));
    }

    /**
     * Gets the property value at `path` of `object`. If the resolved value is
     * `undefined` the `defaultValue` is used in its place.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @param {Array|string} path The path of the property to get.
     * @param {*} [defaultValue] The value returned if the resolved value is `undefined`.
     * @returns {*} Returns the resolved value.
     * @example
     *
     * var object = { 'a': [{ 'b': { 'c': 3 } }] };
     *
     * _.get(object, 'a[0].b.c');
     * // => 3
     *
     * _.get(object, ['a', '0', 'b', 'c']);
     * // => 3
     *
     * _.get(object, 'a.b.c', 'default');
     * // => 'default'
     */
    function get(object, path, defaultValue) {
      var result = object == null ? undefined : baseGet(object, toPath(path), path + '');
      return result === undefined ? defaultValue : result;
    }

    /**
     * Checks if `path` is a direct property.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @param {Array|string} path The path to check.
     * @returns {boolean} Returns `true` if `path` is a direct property, else `false`.
     * @example
     *
     * var object = { 'a': { 'b': { 'c': 3 } } };
     *
     * _.has(object, 'a');
     * // => true
     *
     * _.has(object, 'a.b.c');
     * // => true
     *
     * _.has(object, ['a', 'b', 'c']);
     * // => true
     */
    function has(object, path) {
      if (object == null) {
        return false;
      }
      var result = hasOwnProperty.call(object, path);
      if (!result && !isKey(path)) {
        path = toPath(path);
        object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
        if (object == null) {
          return false;
        }
        path = last(path);
        result = hasOwnProperty.call(object, path);
      }
      return result || (isLength(object.length) && isIndex(path, object.length) &&
        (isArray(object) || isArguments(object)));
    }

    /**
     * Creates an object composed of the inverted keys and values of `object`.
     * If `object` contains duplicate values, subsequent values overwrite property
     * assignments of previous values unless `multiValue` is `true`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to invert.
     * @param {boolean} [multiValue] Allow multiple values per key.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Object} Returns the new inverted object.
     * @example
     *
     * var object = { 'a': 1, 'b': 2, 'c': 1 };
     *
     * _.invert(object);
     * // => { '1': 'c', '2': 'b' }
     *
     * // with `multiValue`
     * _.invert(object, true);
     * // => { '1': ['a', 'c'], '2': ['b'] }
     */
    function invert(object, multiValue, guard) {
      if (guard && isIterateeCall(object, multiValue, guard)) {
        multiValue = null;
      }
      var index = -1,
          props = keys(object),
          length = props.length,
          result = {};

      while (++index < length) {
        var key = props[index],
            value = object[key];

        if (multiValue) {
          if (hasOwnProperty.call(result, value)) {
            result[value].push(key);
          } else {
            result[value] = [key];
          }
        }
        else {
          result[value] = key;
        }
      }
      return result;
    }

    /**
     * Creates an array of the own enumerable property names of `object`.
     *
     * **Note:** Non-object values are coerced to objects. See the
     * [ES spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.keys)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @returns {Array} Returns the array of property names.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.keys(new Foo);
     * // => ['a', 'b'] (iteration order is not guaranteed)
     *
     * _.keys('hi');
     * // => ['0', '1']
     */
    var keys = !nativeKeys ? shimKeys : function(object) {
      var Ctor = object == null ? null : object.constructor;
      if ((typeof Ctor == 'function' && Ctor.prototype === object) ||
          (typeof object != 'function' && isArrayLike(object))) {
        return shimKeys(object);
      }
      return isObject(object) ? nativeKeys(object) : [];
    };

    /**
     * Creates an array of the own and inherited enumerable property names of `object`.
     *
     * **Note:** Non-object values are coerced to objects.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @returns {Array} Returns the array of property names.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.keysIn(new Foo);
     * // => ['a', 'b', 'c'] (iteration order is not guaranteed)
     */
    function keysIn(object) {
      if (object == null) {
        return [];
      }
      if (!isObject(object)) {
        object = Object(object);
      }
      var length = object.length;
      length = (length && isLength(length) &&
        (isArray(object) || isArguments(object)) && length) || 0;

      var Ctor = object.constructor,
          index = -1,
          isProto = typeof Ctor == 'function' && Ctor.prototype === object,
          result = Array(length),
          skipIndexes = length > 0;

      while (++index < length) {
        result[index] = (index + '');
      }
      for (var key in object) {
        if (!(skipIndexes && isIndex(key, length)) &&
            !(key == 'constructor' && (isProto || !hasOwnProperty.call(object, key)))) {
          result.push(key);
        }
      }
      return result;
    }

    /**
     * The opposite of `_.mapValues`; this method creates an object with the
     * same values as `object` and keys generated by running each own enumerable
     * property of `object` through `iteratee`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the new mapped object.
     * @example
     *
     * _.mapKeys({ 'a': 1, 'b': 2 }, function(value, key) {
     *   return key + value;
     * });
     * // => { 'a1': 1, 'b2': 2 }
     */
    var mapKeys = createObjectMapper(true);

    /**
     * Creates an object with the same keys as `object` and values generated by
     * running each own enumerable property of `object` through `iteratee`. The
     * iteratee function is bound to `thisArg` and invoked with three arguments:
     * (value, key, object).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the new mapped object.
     * @example
     *
     * _.mapValues({ 'a': 1, 'b': 2 }, function(n) {
     *   return n * 3;
     * });
     * // => { 'a': 3, 'b': 6 }
     *
     * var users = {
     *   'fred':    { 'user': 'fred',    'age': 40 },
     *   'pebbles': { 'user': 'pebbles', 'age': 1 }
     * };
     *
     * // using the `_.property` callback shorthand
     * _.mapValues(users, 'age');
     * // => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)
     */
    var mapValues = createObjectMapper();

    /**
     * Recursively merges own enumerable properties of the source object(s), that
     * don't resolve to `undefined` into the destination object. Subsequent sources
     * overwrite property assignments of previous sources. If `customizer` is
     * provided it is invoked to produce the merged values of the destination and
     * source properties. If `customizer` returns `undefined` merging is handled
     * by the method instead. The `customizer` is bound to `thisArg` and invoked
     * with five arguments: (objectValue, sourceValue, key, object, source).
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The destination object.
     * @param {...Object} [sources] The source objects.
     * @param {Function} [customizer] The function to customize assigned values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * var users = {
     *   'data': [{ 'user': 'barney' }, { 'user': 'fred' }]
     * };
     *
     * var ages = {
     *   'data': [{ 'age': 36 }, { 'age': 40 }]
     * };
     *
     * _.merge(users, ages);
     * // => { 'data': [{ 'user': 'barney', 'age': 36 }, { 'user': 'fred', 'age': 40 }] }
     *
     * // using a customizer callback
     * var object = {
     *   'fruits': ['apple'],
     *   'vegetables': ['beet']
     * };
     *
     * var other = {
     *   'fruits': ['banana'],
     *   'vegetables': ['carrot']
     * };
     *
     * _.merge(object, other, function(a, b) {
     *   if (_.isArray(a)) {
     *     return a.concat(b);
     *   }
     * });
     * // => { 'fruits': ['apple', 'banana'], 'vegetables': ['beet', 'carrot'] }
     */
    var merge = createAssigner(baseMerge);

    /**
     * The opposite of `_.pick`; this method creates an object composed of the
     * own and inherited enumerable properties of `object` that are not omitted.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The source object.
     * @param {Function|...(string|string[])} [predicate] The function invoked per
     *  iteration or property names to omit, specified as individual property
     *  names or arrays of property names.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Object} Returns the new object.
     * @example
     *
     * var object = { 'user': 'fred', 'age': 40 };
     *
     * _.omit(object, 'age');
     * // => { 'user': 'fred' }
     *
     * _.omit(object, _.isNumber);
     * // => { 'user': 'fred' }
     */
    var omit = restParam(function(object, props) {
      if (object == null) {
        return {};
      }
      if (typeof props[0] != 'function') {
        var props = arrayMap(baseFlatten(props), String);
        return pickByArray(object, baseDifference(keysIn(object), props));
      }
      var predicate = bindCallback(props[0], props[1], 3);
      return pickByCallback(object, function(value, key, object) {
        return !predicate(value, key, object);
      });
    });

    /**
     * Creates a two dimensional array of the key-value pairs for `object`,
     * e.g. `[[key1, value1], [key2, value2]]`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @returns {Array} Returns the new array of key-value pairs.
     * @example
     *
     * _.pairs({ 'barney': 36, 'fred': 40 });
     * // => [['barney', 36], ['fred', 40]] (iteration order is not guaranteed)
     */
    function pairs(object) {
      object = toObject(object);

      var index = -1,
          props = keys(object),
          length = props.length,
          result = Array(length);

      while (++index < length) {
        var key = props[index];
        result[index] = [key, object[key]];
      }
      return result;
    }

    /**
     * Creates an object composed of the picked `object` properties. Property
     * names may be specified as individual arguments or as arrays of property
     * names. If `predicate` is provided it is invoked for each property of `object`
     * picking the properties `predicate` returns truthy for. The predicate is
     * bound to `thisArg` and invoked with three arguments: (value, key, object).
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The source object.
     * @param {Function|...(string|string[])} [predicate] The function invoked per
     *  iteration or property names to pick, specified as individual property
     *  names or arrays of property names.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Object} Returns the new object.
     * @example
     *
     * var object = { 'user': 'fred', 'age': 40 };
     *
     * _.pick(object, 'user');
     * // => { 'user': 'fred' }
     *
     * _.pick(object, _.isString);
     * // => { 'user': 'fred' }
     */
    var pick = restParam(function(object, props) {
      if (object == null) {
        return {};
      }
      return typeof props[0] == 'function'
        ? pickByCallback(object, bindCallback(props[0], props[1], 3))
        : pickByArray(object, baseFlatten(props));
    });

    /**
     * This method is like `_.get` except that if the resolved value is a function
     * it is invoked with the `this` binding of its parent object and its result
     * is returned.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @param {Array|string} path The path of the property to resolve.
     * @param {*} [defaultValue] The value returned if the resolved value is `undefined`.
     * @returns {*} Returns the resolved value.
     * @example
     *
     * var object = { 'a': [{ 'b': { 'c1': 3, 'c2': _.constant(4) } }] };
     *
     * _.result(object, 'a[0].b.c1');
     * // => 3
     *
     * _.result(object, 'a[0].b.c2');
     * // => 4
     *
     * _.result(object, 'a.b.c', 'default');
     * // => 'default'
     *
     * _.result(object, 'a.b.c', _.constant('default'));
     * // => 'default'
     */
    function result(object, path, defaultValue) {
      var result = object == null ? undefined : object[path];
      if (result === undefined) {
        if (object != null && !isKey(path, object)) {
          path = toPath(path);
          object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
          result = object == null ? undefined : object[last(path)];
        }
        result = result === undefined ? defaultValue : result;
      }
      return isFunction(result) ? result.call(object) : result;
    }

    /**
     * Sets the property value of `path` on `object`. If a portion of `path`
     * does not exist it is created.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to augment.
     * @param {Array|string} path The path of the property to set.
     * @param {*} value The value to set.
     * @returns {Object} Returns `object`.
     * @example
     *
     * var object = { 'a': [{ 'b': { 'c': 3 } }] };
     *
     * _.set(object, 'a[0].b.c', 4);
     * console.log(object.a[0].b.c);
     * // => 4
     *
     * _.set(object, 'x[0].y.z', 5);
     * console.log(object.x[0].y.z);
     * // => 5
     */
    function set(object, path, value) {
      if (object == null) {
        return object;
      }
      var pathKey = (path + '');
      path = (object[pathKey] != null || isKey(path, object)) ? [pathKey] : toPath(path);

      var index = -1,
          length = path.length,
          lastIndex = length - 1,
          nested = object;

      while (nested != null && ++index < length) {
        var key = path[index];
        if (isObject(nested)) {
          if (index == lastIndex) {
            nested[key] = value;
          } else if (nested[key] == null) {
            nested[key] = isIndex(path[index + 1]) ? [] : {};
          }
        }
        nested = nested[key];
      }
      return object;
    }

    /**
     * An alternative to `_.reduce`; this method transforms `object` to a new
     * `accumulator` object which is the result of running each of its own enumerable
     * properties through `iteratee`, with each invocation potentially mutating
     * the `accumulator` object. The `iteratee` is bound to `thisArg` and invoked
     * with four arguments: (accumulator, value, key, object). Iteratee functions
     * may exit iteration early by explicitly returning `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Array|Object} object The object to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [accumulator] The custom accumulator value.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the accumulated value.
     * @example
     *
     * _.transform([2, 3, 4], function(result, n) {
     *   result.push(n *= n);
     *   return n % 2 == 0;
     * });
     * // => [4, 9]
     *
     * _.transform({ 'a': 1, 'b': 2 }, function(result, n, key) {
     *   result[key] = n * 3;
     * });
     * // => { 'a': 3, 'b': 6 }
     */
    function transform(object, iteratee, accumulator, thisArg) {
      var isArr = isArray(object) || isTypedArray(object);
      iteratee = getCallback(iteratee, thisArg, 4);

      if (accumulator == null) {
        if (isArr || isObject(object)) {
          var Ctor = object.constructor;
          if (isArr) {
            accumulator = isArray(object) ? new Ctor : [];
          } else {
            accumulator = baseCreate(isFunction(Ctor) ? Ctor.prototype : null);
          }
        } else {
          accumulator = {};
        }
      }
      (isArr ? arrayEach : baseForOwn)(object, function(value, index, object) {
        return iteratee(accumulator, value, index, object);
      });
      return accumulator;
    }

    /**
     * Creates an array of the own enumerable property values of `object`.
     *
     * **Note:** Non-object values are coerced to objects.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @returns {Array} Returns the array of property values.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.values(new Foo);
     * // => [1, 2] (iteration order is not guaranteed)
     *
     * _.values('hi');
     * // => ['h', 'i']
     */
    function values(object) {
      return baseValues(object, keys(object));
    }

    /**
     * Creates an array of the own and inherited enumerable property values
     * of `object`.
     *
     * **Note:** Non-object values are coerced to objects.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @returns {Array} Returns the array of property values.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.valuesIn(new Foo);
     * // => [1, 2, 3] (iteration order is not guaranteed)
     */
    function valuesIn(object) {
      return baseValues(object, keysIn(object));
    }

    /*------------------------------------------------------------------------*/

    /**
     * Checks if `n` is between `start` and up to but not including, `end`. If
     * `end` is not specified it is set to `start` with `start` then set to `0`.
     *
     * @static
     * @memberOf _
     * @category Number
     * @param {number} n The number to check.
     * @param {number} [start=0] The start of the range.
     * @param {number} end The end of the range.
     * @returns {boolean} Returns `true` if `n` is in the range, else `false`.
     * @example
     *
     * _.inRange(3, 2, 4);
     * // => true
     *
     * _.inRange(4, 8);
     * // => true
     *
     * _.inRange(4, 2);
     * // => false
     *
     * _.inRange(2, 2);
     * // => false
     *
     * _.inRange(1.2, 2);
     * // => true
     *
     * _.inRange(5.2, 4);
     * // => false
     */
    function inRange(value, start, end) {
      start = +start || 0;
      if (typeof end === 'undefined') {
        end = start;
        start = 0;
      } else {
        end = +end || 0;
      }
      return value >= nativeMin(start, end) && value < nativeMax(start, end);
    }

    /**
     * Produces a random number between `min` and `max` (inclusive). If only one
     * argument is provided a number between `0` and the given number is returned.
     * If `floating` is `true`, or either `min` or `max` are floats, a floating-point
     * number is returned instead of an integer.
     *
     * @static
     * @memberOf _
     * @category Number
     * @param {number} [min=0] The minimum possible value.
     * @param {number} [max=1] The maximum possible value.
     * @param {boolean} [floating] Specify returning a floating-point number.
     * @returns {number} Returns the random number.
     * @example
     *
     * _.random(0, 5);
     * // => an integer between 0 and 5
     *
     * _.random(5);
     * // => also an integer between 0 and 5
     *
     * _.random(5, true);
     * // => a floating-point number between 0 and 5
     *
     * _.random(1.2, 5.2);
     * // => a floating-point number between 1.2 and 5.2
     */
    function random(min, max, floating) {
      if (floating && isIterateeCall(min, max, floating)) {
        max = floating = null;
      }
      var noMin = min == null,
          noMax = max == null;

      if (floating == null) {
        if (noMax && typeof min == 'boolean') {
          floating = min;
          min = 1;
        }
        else if (typeof max == 'boolean') {
          floating = max;
          noMax = true;
        }
      }
      if (noMin && noMax) {
        max = 1;
        noMax = false;
      }
      min = +min || 0;
      if (noMax) {
        max = min;
        min = 0;
      } else {
        max = +max || 0;
      }
      if (floating || min % 1 || max % 1) {
        var rand = nativeRandom();
        return nativeMin(min + (rand * (max - min + parseFloat('1e-' + ((rand + '').length - 1)))), max);
      }
      return baseRandom(min, max);
    }

    /*------------------------------------------------------------------------*/

    /**
     * Converts `string` to [camel case](https://en.wikipedia.org/wiki/CamelCase).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to convert.
     * @returns {string} Returns the camel cased string.
     * @example
     *
     * _.camelCase('Foo Bar');
     * // => 'fooBar'
     *
     * _.camelCase('--foo-bar');
     * // => 'fooBar'
     *
     * _.camelCase('__foo_bar__');
     * // => 'fooBar'
     */
    var camelCase = createCompounder(function(result, word, index) {
      word = word.toLowerCase();
      return result + (index ? (word.charAt(0).toUpperCase() + word.slice(1)) : word);
    });

    /**
     * Capitalizes the first character of `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to capitalize.
     * @returns {string} Returns the capitalized string.
     * @example
     *
     * _.capitalize('fred');
     * // => 'Fred'
     */
    function capitalize(string) {
      string = baseToString(string);
      return string && (string.charAt(0).toUpperCase() + string.slice(1));
    }

    /**
     * Deburrs `string` by converting [latin-1 supplementary letters](https://en.wikipedia.org/wiki/Latin-1_Supplement_(Unicode_block)#Character_table)
     * to basic latin letters and removing [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to deburr.
     * @returns {string} Returns the deburred string.
     * @example
     *
     * _.deburr('déjà vu');
     * // => 'deja vu'
     */
    function deburr(string) {
      string = baseToString(string);
      return string && string.replace(reLatin1, deburrLetter).replace(reComboMark, '');
    }

    /**
     * Checks if `string` ends with the given target string.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to search.
     * @param {string} [target] The string to search for.
     * @param {number} [position=string.length] The position to search from.
     * @returns {boolean} Returns `true` if `string` ends with `target`, else `false`.
     * @example
     *
     * _.endsWith('abc', 'c');
     * // => true
     *
     * _.endsWith('abc', 'b');
     * // => false
     *
     * _.endsWith('abc', 'b', 2);
     * // => true
     */
    function endsWith(string, target, position) {
      string = baseToString(string);
      target = (target + '');

      var length = string.length;
      position = position === undefined
        ? length
        : nativeMin(position < 0 ? 0 : (+position || 0), length);

      position -= target.length;
      return position >= 0 && string.indexOf(target, position) == position;
    }

    /**
     * Converts the characters "&", "<", ">", '"', "'", and "\`", in `string` to
     * their corresponding HTML entities.
     *
     * **Note:** No other characters are escaped. To escape additional characters
     * use a third-party library like [_he_](https://mths.be/he).
     *
     * Though the ">" character is escaped for symmetry, characters like
     * ">" and "/" don't need escaping in HTML and have no special meaning
     * unless they're part of a tag or unquoted attribute value.
     * See [Mathias Bynens's article](https://mathiasbynens.be/notes/ambiguous-ampersands)
     * (under "semi-related fun fact") for more details.
     *
     * Backticks are escaped because in Internet Explorer < 9, they can break out
     * of attribute values or HTML comments. See [#59](https://html5sec.org/#59),
     * [#102](https://html5sec.org/#102), [#108](https://html5sec.org/#108), and
     * [#133](https://html5sec.org/#133) of the [HTML5 Security Cheatsheet](https://html5sec.org/)
     * for more details.
     *
     * When working with HTML you should always [quote attribute values](http://wonko.com/post/html-escaping)
     * to reduce XSS vectors.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to escape.
     * @returns {string} Returns the escaped string.
     * @example
     *
     * _.escape('fred, barney, & pebbles');
     * // => 'fred, barney, &amp; pebbles'
     */
    function escape(string) {
      // Reset `lastIndex` because in IE < 9 `String#replace` does not.
      string = baseToString(string);
      return (string && reHasUnescapedHtml.test(string))
        ? string.replace(reUnescapedHtml, escapeHtmlChar)
        : string;
    }

    /**
     * Escapes the `RegExp` special characters "\", "/", "^", "$", ".", "|", "?",
     * "*", "+", "(", ")", "[", "]", "{" and "}" in `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to escape.
     * @returns {string} Returns the escaped string.
     * @example
     *
     * _.escapeRegExp('[lodash](https://lodash.com/)');
     * // => '\[lodash\]\(https:\/\/lodash\.com\/\)'
     */
    function escapeRegExp(string) {
      string = baseToString(string);
      return (string && reHasRegExpChars.test(string))
        ? string.replace(reRegExpChars, '\\$&')
        : string;
    }

    /**
     * Converts `string` to [kebab case](https://en.wikipedia.org/wiki/Letter_case#Special_case_styles).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to convert.
     * @returns {string} Returns the kebab cased string.
     * @example
     *
     * _.kebabCase('Foo Bar');
     * // => 'foo-bar'
     *
     * _.kebabCase('fooBar');
     * // => 'foo-bar'
     *
     * _.kebabCase('__foo_bar__');
     * // => 'foo-bar'
     */
    var kebabCase = createCompounder(function(result, word, index) {
      return result + (index ? '-' : '') + word.toLowerCase();
    });

    /**
     * Pads `string` on the left and right sides if it's shorter than `length`.
     * Padding characters are truncated if they can't be evenly divided by `length`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to pad.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the padded string.
     * @example
     *
     * _.pad('abc', 8);
     * // => '  abc   '
     *
     * _.pad('abc', 8, '_-');
     * // => '_-abc_-_'
     *
     * _.pad('abc', 3);
     * // => 'abc'
     */
    function pad(string, length, chars) {
      string = baseToString(string);
      length = +length;

      var strLength = string.length;
      if (strLength >= length || !nativeIsFinite(length)) {
        return string;
      }
      var mid = (length - strLength) / 2,
          leftLength = floor(mid),
          rightLength = ceil(mid);

      chars = createPadding('', rightLength, chars);
      return chars.slice(0, leftLength) + string + chars;
    }

    /**
     * Pads `string` on the left side if it's shorter than `length`. Padding
     * characters are truncated if they exceed `length`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to pad.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the padded string.
     * @example
     *
     * _.padLeft('abc', 6);
     * // => '   abc'
     *
     * _.padLeft('abc', 6, '_-');
     * // => '_-_abc'
     *
     * _.padLeft('abc', 3);
     * // => 'abc'
     */
    var padLeft = createPadDir();

    /**
     * Pads `string` on the right side if it's shorter than `length`. Padding
     * characters are truncated if they exceed `length`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to pad.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the padded string.
     * @example
     *
     * _.padRight('abc', 6);
     * // => 'abc   '
     *
     * _.padRight('abc', 6, '_-');
     * // => 'abc_-_'
     *
     * _.padRight('abc', 3);
     * // => 'abc'
     */
    var padRight = createPadDir(true);

    /**
     * Converts `string` to an integer of the specified radix. If `radix` is
     * `undefined` or `0`, a `radix` of `10` is used unless `value` is a hexadecimal,
     * in which case a `radix` of `16` is used.
     *
     * **Note:** This method aligns with the [ES5 implementation](https://es5.github.io/#E)
     * of `parseInt`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} string The string to convert.
     * @param {number} [radix] The radix to interpret `value` by.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {number} Returns the converted integer.
     * @example
     *
     * _.parseInt('08');
     * // => 8
     *
     * _.map(['6', '08', '10'], _.parseInt);
     * // => [6, 8, 10]
     */
    function parseInt(string, radix, guard) {
      if (guard && isIterateeCall(string, radix, guard)) {
        radix = 0;
      }
      return nativeParseInt(string, radix);
    }
    // Fallback for environments with pre-ES5 implementations.
    if (nativeParseInt(whitespace + '08') != 8) {
      parseInt = function(string, radix, guard) {
        // Firefox < 21 and Opera < 15 follow ES3 for `parseInt`.
        // Chrome fails to trim leading <BOM> whitespace characters.
        // See https://code.google.com/p/v8/issues/detail?id=3109 for more details.
        if (guard ? isIterateeCall(string, radix, guard) : radix == null) {
          radix = 0;
        } else if (radix) {
          radix = +radix;
        }
        string = trim(string);
        return nativeParseInt(string, radix || (reHasHexPrefix.test(string) ? 16 : 10));
      };
    }

    /**
     * Repeats the given string `n` times.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to repeat.
     * @param {number} [n=0] The number of times to repeat the string.
     * @returns {string} Returns the repeated string.
     * @example
     *
     * _.repeat('*', 3);
     * // => '***'
     *
     * _.repeat('abc', 2);
     * // => 'abcabc'
     *
     * _.repeat('abc', 0);
     * // => ''
     */
    function repeat(string, n) {
      var result = '';
      string = baseToString(string);
      n = +n;
      if (n < 1 || !string || !nativeIsFinite(n)) {
        return result;
      }
      // Leverage the exponentiation by squaring algorithm for a faster repeat.
      // See https://en.wikipedia.org/wiki/Exponentiation_by_squaring for more details.
      do {
        if (n % 2) {
          result += string;
        }
        n = floor(n / 2);
        string += string;
      } while (n);

      return result;
    }

    /**
     * Converts `string` to [snake case](https://en.wikipedia.org/wiki/Snake_case).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to convert.
     * @returns {string} Returns the snake cased string.
     * @example
     *
     * _.snakeCase('Foo Bar');
     * // => 'foo_bar'
     *
     * _.snakeCase('fooBar');
     * // => 'foo_bar'
     *
     * _.snakeCase('--foo-bar');
     * // => 'foo_bar'
     */
    var snakeCase = createCompounder(function(result, word, index) {
      return result + (index ? '_' : '') + word.toLowerCase();
    });

    /**
     * Converts `string` to [start case](https://en.wikipedia.org/wiki/Letter_case#Stylistic_or_specialised_usage).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to convert.
     * @returns {string} Returns the start cased string.
     * @example
     *
     * _.startCase('--foo-bar');
     * // => 'Foo Bar'
     *
     * _.startCase('fooBar');
     * // => 'Foo Bar'
     *
     * _.startCase('__foo_bar__');
     * // => 'Foo Bar'
     */
    var startCase = createCompounder(function(result, word, index) {
      return result + (index ? ' ' : '') + (word.charAt(0).toUpperCase() + word.slice(1));
    });

    /**
     * Checks if `string` starts with the given target string.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to search.
     * @param {string} [target] The string to search for.
     * @param {number} [position=0] The position to search from.
     * @returns {boolean} Returns `true` if `string` starts with `target`, else `false`.
     * @example
     *
     * _.startsWith('abc', 'a');
     * // => true
     *
     * _.startsWith('abc', 'b');
     * // => false
     *
     * _.startsWith('abc', 'b', 1);
     * // => true
     */
    function startsWith(string, target, position) {
      string = baseToString(string);
      position = position == null
        ? 0
        : nativeMin(position < 0 ? 0 : (+position || 0), string.length);

      return string.lastIndexOf(target, position) == position;
    }

    /**
     * Creates a compiled template function that can interpolate data properties
     * in "interpolate" delimiters, HTML-escape interpolated data properties in
     * "escape" delimiters, and execute JavaScript in "evaluate" delimiters. Data
     * properties may be accessed as free variables in the template. If a setting
     * object is provided it takes precedence over `_.templateSettings` values.
     *
     * **Note:** In the development build `_.template` utilizes
     * [sourceURLs](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl)
     * for easier debugging.
     *
     * For more information on precompiling templates see
     * [lodash's custom builds documentation](https://lodash.com/custom-builds).
     *
     * For more information on Chrome extension sandboxes see
     * [Chrome's extensions documentation](https://developer.chrome.com/extensions/sandboxingEval).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The template string.
     * @param {Object} [options] The options object.
     * @param {RegExp} [options.escape] The HTML "escape" delimiter.
     * @param {RegExp} [options.evaluate] The "evaluate" delimiter.
     * @param {Object} [options.imports] An object to import into the template as free variables.
     * @param {RegExp} [options.interpolate] The "interpolate" delimiter.
     * @param {string} [options.sourceURL] The sourceURL of the template's compiled source.
     * @param {string} [options.variable] The data object variable name.
     * @param- {Object} [otherOptions] Enables the legacy `options` param signature.
     * @returns {Function} Returns the compiled template function.
     * @example
     *
     * // using the "interpolate" delimiter to create a compiled template
     * var compiled = _.template('hello <%= user %>!');
     * compiled({ 'user': 'fred' });
     * // => 'hello fred!'
     *
     * // using the HTML "escape" delimiter to escape data property values
     * var compiled = _.template('<b><%- value %></b>');
     * compiled({ 'value': '<script>' });
     * // => '<b>&lt;script&gt;</b>'
     *
     * // using the "evaluate" delimiter to execute JavaScript and generate HTML
     * var compiled = _.template('<% _.forEach(users, function(user) { %><li><%- user %></li><% }); %>');
     * compiled({ 'users': ['fred', 'barney'] });
     * // => '<li>fred</li><li>barney</li>'
     *
     * // using the internal `print` function in "evaluate" delimiters
     * var compiled = _.template('<% print("hello " + user); %>!');
     * compiled({ 'user': 'barney' });
     * // => 'hello barney!'
     *
     * // using the ES delimiter as an alternative to the default "interpolate" delimiter
     * var compiled = _.template('hello ${ user }!');
     * compiled({ 'user': 'pebbles' });
     * // => 'hello pebbles!'
     *
     * // using custom template delimiters
     * _.templateSettings.interpolate = /{{([\s\S]+?)}}/g;
     * var compiled = _.template('hello {{ user }}!');
     * compiled({ 'user': 'mustache' });
     * // => 'hello mustache!'
     *
     * // using backslashes to treat delimiters as plain text
     * var compiled = _.template('<%= "\\<%- value %\\>" %>');
     * compiled({ 'value': 'ignored' });
     * // => '<%- value %>'
     *
     * // using the `imports` option to import `jQuery` as `jq`
     * var text = '<% jq.each(users, function(user) { %><li><%- user %></li><% }); %>';
     * var compiled = _.template(text, { 'imports': { 'jq': jQuery } });
     * compiled({ 'users': ['fred', 'barney'] });
     * // => '<li>fred</li><li>barney</li>'
     *
     * // using the `sourceURL` option to specify a custom sourceURL for the template
     * var compiled = _.template('hello <%= user %>!', { 'sourceURL': '/basic/greeting.jst' });
     * compiled(data);
     * // => find the source of "greeting.jst" under the Sources tab or Resources panel of the web inspector
     *
     * // using the `variable` option to ensure a with-statement isn't used in the compiled template
     * var compiled = _.template('hi <%= data.user %>!', { 'variable': 'data' });
     * compiled.source;
     * // => function(data) {
     * //   var __t, __p = '';
     * //   __p += 'hi ' + ((__t = ( data.user )) == null ? '' : __t) + '!';
     * //   return __p;
     * // }
     *
     * // using the `source` property to inline compiled templates for meaningful
     * // line numbers in error messages and a stack trace
     * fs.writeFileSync(path.join(cwd, 'jst.js'), '\
     *   var JST = {\
     *     "main": ' + _.template(mainText).source + '\
     *   };\
     * ');
     */
    function template(string, options, otherOptions) {
      // Based on John Resig's `tmpl` implementation (http://ejohn.org/blog/javascript-micro-templating/)
      // and Laura Doktorova's doT.js (https://github.com/olado/doT).
      var settings = lodash.templateSettings;

      if (otherOptions && isIterateeCall(string, options, otherOptions)) {
        options = otherOptions = null;
      }
      string = baseToString(string);
      options = assignWith(baseAssign({}, otherOptions || options), settings, assignOwnDefaults);

      var imports = assignWith(baseAssign({}, options.imports), settings.imports, assignOwnDefaults),
          importsKeys = keys(imports),
          importsValues = baseValues(imports, importsKeys);

      var isEscaping,
          isEvaluating,
          index = 0,
          interpolate = options.interpolate || reNoMatch,
          source = "__p += '";

      // Compile the regexp to match each delimiter.
      var reDelimiters = RegExp(
        (options.escape || reNoMatch).source + '|' +
        interpolate.source + '|' +
        (interpolate === reInterpolate ? reEsTemplate : reNoMatch).source + '|' +
        (options.evaluate || reNoMatch).source + '|$'
      , 'g');

      // Use a sourceURL for easier debugging.
      var sourceURL = '//# sourceURL=' +
        ('sourceURL' in options
          ? options.sourceURL
          : ('lodash.templateSources[' + (++templateCounter) + ']')
        ) + '\n';

      string.replace(reDelimiters, function(match, escapeValue, interpolateValue, esTemplateValue, evaluateValue, offset) {
        interpolateValue || (interpolateValue = esTemplateValue);

        // Escape characters that can't be included in string literals.
        source += string.slice(index, offset).replace(reUnescapedString, escapeStringChar);

        // Replace delimiters with snippets.
        if (escapeValue) {
          isEscaping = true;
          source += "' +\n__e(" + escapeValue + ") +\n'";
        }
        if (evaluateValue) {
          isEvaluating = true;
          source += "';\n" + evaluateValue + ";\n__p += '";
        }
        if (interpolateValue) {
          source += "' +\n((__t = (" + interpolateValue + ")) == null ? '' : __t) +\n'";
        }
        index = offset + match.length;

        // The JS engine embedded in Adobe products requires returning the `match`
        // string in order to produce the correct `offset` value.
        return match;
      });

      source += "';\n";

      // If `variable` is not specified wrap a with-statement around the generated
      // code to add the data object to the top of the scope chain.
      var variable = options.variable;
      if (!variable) {
        source = 'with (obj) {\n' + source + '\n}\n';
      }
      // Cleanup code by stripping empty strings.
      source = (isEvaluating ? source.replace(reEmptyStringLeading, '') : source)
        .replace(reEmptyStringMiddle, '$1')
        .replace(reEmptyStringTrailing, '$1;');

      // Frame code as the function body.
      source = 'function(' + (variable || 'obj') + ') {\n' +
        (variable
          ? ''
          : 'obj || (obj = {});\n'
        ) +
        "var __t, __p = ''" +
        (isEscaping
           ? ', __e = _.escape'
           : ''
        ) +
        (isEvaluating
          ? ', __j = Array.prototype.join;\n' +
            "function print() { __p += __j.call(arguments, '') }\n"
          : ';\n'
        ) +
        source +
        'return __p\n}';

      var result = attempt(function() {
        return Function(importsKeys, sourceURL + 'return ' + source).apply(undefined, importsValues);
      });

      // Provide the compiled function's source by its `toString` method or
      // the `source` property as a convenience for inlining compiled templates.
      result.source = source;
      if (isError(result)) {
        throw result;
      }
      return result;
    }

    /**
     * Removes leading and trailing whitespace or specified characters from `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to trim.
     * @param {string} [chars=whitespace] The characters to trim.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the trimmed string.
     * @example
     *
     * _.trim('  abc  ');
     * // => 'abc'
     *
     * _.trim('-_-abc-_-', '_-');
     * // => 'abc'
     *
     * _.map(['  foo  ', '  bar  '], _.trim);
     * // => ['foo', 'bar']
     */
    function trim(string, chars, guard) {
      var value = string;
      string = baseToString(string);
      if (!string) {
        return string;
      }
      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
        return string.slice(trimmedLeftIndex(string), trimmedRightIndex(string) + 1);
      }
      chars = (chars + '');
      return string.slice(charsLeftIndex(string, chars), charsRightIndex(string, chars) + 1);
    }

    /**
     * Removes leading whitespace or specified characters from `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to trim.
     * @param {string} [chars=whitespace] The characters to trim.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the trimmed string.
     * @example
     *
     * _.trimLeft('  abc  ');
     * // => 'abc  '
     *
     * _.trimLeft('-_-abc-_-', '_-');
     * // => 'abc-_-'
     */
    function trimLeft(string, chars, guard) {
      var value = string;
      string = baseToString(string);
      if (!string) {
        return string;
      }
      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
        return string.slice(trimmedLeftIndex(string));
      }
      return string.slice(charsLeftIndex(string, (chars + '')));
    }

    /**
     * Removes trailing whitespace or specified characters from `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to trim.
     * @param {string} [chars=whitespace] The characters to trim.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the trimmed string.
     * @example
     *
     * _.trimRight('  abc  ');
     * // => '  abc'
     *
     * _.trimRight('-_-abc-_-', '_-');
     * // => '-_-abc'
     */
    function trimRight(string, chars, guard) {
      var value = string;
      string = baseToString(string);
      if (!string) {
        return string;
      }
      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
        return string.slice(0, trimmedRightIndex(string) + 1);
      }
      return string.slice(0, charsRightIndex(string, (chars + '')) + 1);
    }

    /**
     * Truncates `string` if it's longer than the given maximum string length.
     * The last characters of the truncated string are replaced with the omission
     * string which defaults to "...".
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to truncate.
     * @param {Object|number} [options] The options object or maximum string length.
     * @param {number} [options.length=30] The maximum string length.
     * @param {string} [options.omission='...'] The string to indicate text is omitted.
     * @param {RegExp|string} [options.separator] The separator pattern to truncate to.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the truncated string.
     * @example
     *
     * _.trunc('hi-diddly-ho there, neighborino');
     * // => 'hi-diddly-ho there, neighbo...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', 24);
     * // => 'hi-diddly-ho there, n...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', {
     *   'length': 24,
     *   'separator': ' '
     * });
     * // => 'hi-diddly-ho there,...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', {
     *   'length': 24,
     *   'separator': /,? +/
     * });
     * // => 'hi-diddly-ho there...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', {
     *   'omission': ' [...]'
     * });
     * // => 'hi-diddly-ho there, neig [...]'
     */
    function trunc(string, options, guard) {
      if (guard && isIterateeCall(string, options, guard)) {
        options = null;
      }
      var length = DEFAULT_TRUNC_LENGTH,
          omission = DEFAULT_TRUNC_OMISSION;

      if (options != null) {
        if (isObject(options)) {
          var separator = 'separator' in options ? options.separator : separator;
          length = 'length' in options ? (+options.length || 0) : length;
          omission = 'omission' in options ? baseToString(options.omission) : omission;
        } else {
          length = +options || 0;
        }
      }
      string = baseToString(string);
      if (length >= string.length) {
        return string;
      }
      var end = length - omission.length;
      if (end < 1) {
        return omission;
      }
      var result = string.slice(0, end);
      if (separator == null) {
        return result + omission;
      }
      if (isRegExp(separator)) {
        if (string.slice(end).search(separator)) {
          var match,
              newEnd,
              substring = string.slice(0, end);

          if (!separator.global) {
            separator = RegExp(separator.source, (reFlags.exec(separator) || '') + 'g');
          }
          separator.lastIndex = 0;
          while ((match = separator.exec(substring))) {
            newEnd = match.index;
          }
          result = result.slice(0, newEnd == null ? end : newEnd);
        }
      } else if (string.indexOf(separator, end) != end) {
        var index = result.lastIndexOf(separator);
        if (index > -1) {
          result = result.slice(0, index);
        }
      }
      return result + omission;
    }

    /**
     * The inverse of `_.escape`; this method converts the HTML entities
     * `&amp;`, `&lt;`, `&gt;`, `&quot;`, `&#39;`, and `&#96;` in `string` to their
     * corresponding characters.
     *
     * **Note:** No other HTML entities are unescaped. To unescape additional HTML
     * entities use a third-party library like [_he_](https://mths.be/he).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to unescape.
     * @returns {string} Returns the unescaped string.
     * @example
     *
     * _.unescape('fred, barney, &amp; pebbles');
     * // => 'fred, barney, & pebbles'
     */
    function unescape(string) {
      string = baseToString(string);
      return (string && reHasEscapedHtml.test(string))
        ? string.replace(reEscapedHtml, unescapeHtmlChar)
        : string;
    }

    /**
     * Splits `string` into an array of its words.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to inspect.
     * @param {RegExp|string} [pattern] The pattern to match words.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the words of `string`.
     * @example
     *
     * _.words('fred, barney, & pebbles');
     * // => ['fred', 'barney', 'pebbles']
     *
     * _.words('fred, barney, & pebbles', /[^, ]+/g);
     * // => ['fred', 'barney', '&', 'pebbles']
     */
    function words(string, pattern, guard) {
      if (guard && isIterateeCall(string, pattern, guard)) {
        pattern = null;
      }
      string = baseToString(string);
      return string.match(pattern || reWords) || [];
    }

    /*------------------------------------------------------------------------*/

    /**
     * Attempts to invoke `func`, returning either the result or the caught error
     * object. Any additional arguments are provided to `func` when it is invoked.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Function} func The function to attempt.
     * @returns {*} Returns the `func` result or error object.
     * @example
     *
     * // avoid throwing errors for invalid selectors
     * var elements = _.attempt(function(selector) {
     *   return document.querySelectorAll(selector);
     * }, '>_>');
     *
     * if (_.isError(elements)) {
     *   elements = [];
     * }
     */
    var attempt = restParam(function(func, args) {
      try {
        return func.apply(undefined, args);
      } catch(e) {
        return isError(e) ? e : new Error(e);
      }
    });

    /**
     * Creates a function that invokes `func` with the `this` binding of `thisArg`
     * and arguments of the created function. If `func` is a property name the
     * created callback returns the property value for a given element. If `func`
     * is an object the created callback returns `true` for elements that contain
     * the equivalent object properties, otherwise it returns `false`.
     *
     * @static
     * @memberOf _
     * @alias iteratee
     * @category Utility
     * @param {*} [func=_.identity] The value to convert to a callback.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Function} Returns the callback.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * // wrap to create custom callback shorthands
     * _.callback = _.wrap(_.callback, function(callback, func, thisArg) {
     *   var match = /^(.+?)__([gl]t)(.+)$/.exec(func);
     *   if (!match) {
     *     return callback(func, thisArg);
     *   }
     *   return function(object) {
     *     return match[2] == 'gt'
     *       ? object[match[1]] > match[3]
     *       : object[match[1]] < match[3];
     *   };
     * });
     *
     * _.filter(users, 'age__gt36');
     * // => [{ 'user': 'fred', 'age': 40 }]
     */
    function callback(func, thisArg, guard) {
      if (guard && isIterateeCall(func, thisArg, guard)) {
        thisArg = null;
      }
      return isObjectLike(func)
        ? matches(func)
        : baseCallback(func, thisArg);
    }

    /**
     * Creates a function that returns `value`.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {*} value The value to return from the new function.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var object = { 'user': 'fred' };
     * var getter = _.constant(object);
     *
     * getter() === object;
     * // => true
     */
    function constant(value) {
      return function() {
        return value;
      };
    }

    /**
     * This method returns the first argument provided to it.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {*} value Any value.
     * @returns {*} Returns `value`.
     * @example
     *
     * var object = { 'user': 'fred' };
     *
     * _.identity(object) === object;
     * // => true
     */
    function identity(value) {
      return value;
    }

    /**
     * Creates a function that performs a deep comparison between a given object
     * and `source`, returning `true` if the given object has equivalent property
     * values, else `false`.
     *
     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
     * numbers, `Object` objects, regexes, and strings. Objects are compared by
     * their own, not inherited, enumerable properties. For comparing a single
     * own or inherited property value see `_.matchesProperty`.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Object} source The object of property values to match.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'active': true },
     *   { 'user': 'fred',   'age': 40, 'active': false }
     * ];
     *
     * _.filter(users, _.matches({ 'age': 40, 'active': false }));
     * // => [{ 'user': 'fred', 'age': 40, 'active': false }]
     */
    function matches(source) {
      return baseMatches(baseClone(source, true));
    }

    /**
     * Creates a function that compares the property value of `path` on a given
     * object to `value`.
     *
     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
     * numbers, `Object` objects, regexes, and strings. Objects are compared by
     * their own, not inherited, enumerable properties.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Array|string} path The path of the property to get.
     * @param {*} srcValue The value to match.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var users = [
     *   { 'user': 'barney' },
     *   { 'user': 'fred' }
     * ];
     *
     * _.find(users, _.matchesProperty('user', 'fred'));
     * // => { 'user': 'fred' }
     */
    function matchesProperty(path, srcValue) {
      return baseMatchesProperty(path, baseClone(srcValue, true));
    }

    /**
     * Creates a function that invokes the method at `path` on a given object.
     * Any additional arguments are provided to the invoked method.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Array|string} path The path of the method to invoke.
     * @param {...*} [args] The arguments to invoke the method with.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var objects = [
     *   { 'a': { 'b': { 'c': _.constant(2) } } },
     *   { 'a': { 'b': { 'c': _.constant(1) } } }
     * ];
     *
     * _.map(objects, _.method('a.b.c'));
     * // => [2, 1]
     *
     * _.invoke(_.sortBy(objects, _.method(['a', 'b', 'c'])), 'a.b.c');
     * // => [1, 2]
     */
    var method = restParam(function(path, args) {
      return function(object) {
        return invokePath(object, path, args);
      };
    });

    /**
     * The opposite of `_.method`; this method creates a function that invokes
     * the method at a given path on `object`. Any additional arguments are
     * provided to the invoked method.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Object} object The object to query.
     * @param {...*} [args] The arguments to invoke the method with.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var array = _.times(3, _.constant),
     *     object = { 'a': array, 'b': array, 'c': array };
     *
     * _.map(['a[2]', 'c[0]'], _.methodOf(object));
     * // => [2, 0]
     *
     * _.map([['a', '2'], ['c', '0']], _.methodOf(object));
     * // => [2, 0]
     */
    var methodOf = restParam(function(object, args) {
      return function(path) {
        return invokePath(object, path, args);
      };
    });

    /**
     * Adds all own enumerable function properties of a source object to the
     * destination object. If `object` is a function then methods are added to
     * its prototype as well.
     *
     * **Note:** Use `_.runInContext` to create a pristine `lodash` function to
     * avoid conflicts caused by modifying the original.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Function|Object} [object=lodash] The destination object.
     * @param {Object} source The object of functions to add.
     * @param {Object} [options] The options object.
     * @param {boolean} [options.chain=true] Specify whether the functions added
     *  are chainable.
     * @returns {Function|Object} Returns `object`.
     * @example
     *
     * function vowels(string) {
     *   return _.filter(string, function(v) {
     *     return /[aeiou]/i.test(v);
     *   });
     * }
     *
     * _.mixin({ 'vowels': vowels });
     * _.vowels('fred');
     * // => ['e']
     *
     * _('fred').vowels().value();
     * // => ['e']
     *
     * _.mixin({ 'vowels': vowels }, { 'chain': false });
     * _('fred').vowels();
     * // => ['e']
     */
    function mixin(object, source, options) {
      if (options == null) {
        var isObj = isObject(source),
            props = isObj ? keys(source) : null,
            methodNames = (props && props.length) ? baseFunctions(source, props) : null;

        if (!(methodNames ? methodNames.length : isObj)) {
          methodNames = false;
          options = source;
          source = object;
          object = this;
        }
      }
      if (!methodNames) {
        methodNames = baseFunctions(source, keys(source));
      }
      var chain = true,
          index = -1,
          isFunc = isFunction(object),
          length = methodNames.length;

      if (options === false) {
        chain = false;
      } else if (isObject(options) && 'chain' in options) {
        chain = options.chain;
      }
      while (++index < length) {
        var methodName = methodNames[index],
            func = source[methodName];

        object[methodName] = func;
        if (isFunc) {
          object.prototype[methodName] = (function(func) {
            return function() {
              var chainAll = this.__chain__;
              if (chain || chainAll) {
                var result = object(this.__wrapped__),
                    actions = result.__actions__ = arrayCopy(this.__actions__);

                actions.push({ 'func': func, 'args': arguments, 'thisArg': object });
                result.__chain__ = chainAll;
                return result;
              }
              var args = [this.value()];
              push.apply(args, arguments);
              return func.apply(object, args);
            };
          }(func));
        }
      }
      return object;
    }

    /**
     * Reverts the `_` variable to its previous value and returns a reference to
     * the `lodash` function.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @returns {Function} Returns the `lodash` function.
     * @example
     *
     * var lodash = _.noConflict();
     */
    function noConflict() {
      context._ = oldDash;
      return this;
    }

    /**
     * A no-operation function that returns `undefined` regardless of the
     * arguments it receives.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @example
     *
     * var object = { 'user': 'fred' };
     *
     * _.noop(object) === undefined;
     * // => true
     */
    function noop() {
      // No operation performed.
    }

    /**
     * Creates a function that returns the property value at `path` on a
     * given object.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Array|string} path The path of the property to get.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var objects = [
     *   { 'a': { 'b': { 'c': 2 } } },
     *   { 'a': { 'b': { 'c': 1 } } }
     * ];
     *
     * _.map(objects, _.property('a.b.c'));
     * // => [2, 1]
     *
     * _.pluck(_.sortBy(objects, _.property(['a', 'b', 'c'])), 'a.b.c');
     * // => [1, 2]
     */
    function property(path) {
      return isKey(path) ? baseProperty(path) : basePropertyDeep(path);
    }

    /**
     * The opposite of `_.property`; this method creates a function that returns
     * the property value at a given path on `object`.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Object} object The object to query.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var array = [0, 1, 2],
     *     object = { 'a': array, 'b': array, 'c': array };
     *
     * _.map(['a[2]', 'c[0]'], _.propertyOf(object));
     * // => [2, 0]
     *
     * _.map([['a', '2'], ['c', '0']], _.propertyOf(object));
     * // => [2, 0]
     */
    function propertyOf(object) {
      return function(path) {
        return baseGet(object, toPath(path), path + '');
      };
    }

    /**
     * Creates an array of numbers (positive and/or negative) progressing from
     * `start` up to, but not including, `end`. If `end` is not specified it is
     * set to `start` with `start` then set to `0`. If `end` is less than `start`
     * a zero-length range is created unless a negative `step` is specified.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {number} [start=0] The start of the range.
     * @param {number} end The end of the range.
     * @param {number} [step=1] The value to increment or decrement by.
     * @returns {Array} Returns the new array of numbers.
     * @example
     *
     * _.range(4);
     * // => [0, 1, 2, 3]
     *
     * _.range(1, 5);
     * // => [1, 2, 3, 4]
     *
     * _.range(0, 20, 5);
     * // => [0, 5, 10, 15]
     *
     * _.range(0, -4, -1);
     * // => [0, -1, -2, -3]
     *
     * _.range(1, 4, 0);
     * // => [1, 1, 1]
     *
     * _.range(0);
     * // => []
     */
    function range(start, end, step) {
      if (step && isIterateeCall(start, end, step)) {
        end = step = null;
      }
      start = +start || 0;
      step = step == null ? 1 : (+step || 0);

      if (end == null) {
        end = start;
        start = 0;
      } else {
        end = +end || 0;
      }
      // Use `Array(length)` so engines like Chakra and V8 avoid slower modes.
      // See https://youtu.be/XAqIpGU8ZZk#t=17m25s for more details.
      var index = -1,
          length = nativeMax(ceil((end - start) / (step || 1)), 0),
          result = Array(length);

      while (++index < length) {
        result[index] = start;
        start += step;
      }
      return result;
    }

    /**
     * Invokes the iteratee function `n` times, returning an array of the results
     * of each invocation. The `iteratee` is bound to `thisArg` and invoked with
     * one argument; (index).
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {number} n The number of times to invoke `iteratee`.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the array of results.
     * @example
     *
     * var diceRolls = _.times(3, _.partial(_.random, 1, 6, false));
     * // => [3, 6, 4]
     *
     * _.times(3, function(n) {
     *   mage.castSpell(n);
     * });
     * // => invokes `mage.castSpell(n)` three times with `n` of `0`, `1`, and `2`
     *
     * _.times(3, function(n) {
     *   this.cast(n);
     * }, mage);
     * // => also invokes `mage.castSpell(n)` three times
     */
    function times(n, iteratee, thisArg) {
      n = floor(n);

      // Exit early to avoid a JSC JIT bug in Safari 8
      // where `Array(0)` is treated as `Array(1)`.
      if (n < 1 || !nativeIsFinite(n)) {
        return [];
      }
      var index = -1,
          result = Array(nativeMin(n, MAX_ARRAY_LENGTH));

      iteratee = bindCallback(iteratee, thisArg, 1);
      while (++index < n) {
        if (index < MAX_ARRAY_LENGTH) {
          result[index] = iteratee(index);
        } else {
          iteratee(index);
        }
      }
      return result;
    }

    /**
     * Generates a unique ID. If `prefix` is provided the ID is appended to it.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {string} [prefix] The value to prefix the ID with.
     * @returns {string} Returns the unique ID.
     * @example
     *
     * _.uniqueId('contact_');
     * // => 'contact_104'
     *
     * _.uniqueId();
     * // => '105'
     */
    function uniqueId(prefix) {
      var id = ++idCounter;
      return baseToString(prefix) + id;
    }

    /*------------------------------------------------------------------------*/

    /**
     * Adds two numbers.
     *
     * @static
     * @memberOf _
     * @category Math
     * @param {number} augend The first number to add.
     * @param {number} addend The second number to add.
     * @returns {number} Returns the sum.
     * @example
     *
     * _.add(6, 4);
     * // => 10
     */
    function add(augend, addend) {
      return (+augend || 0) + (+addend || 0);
    }

    /**
     * Gets the maximum value of `collection`. If `collection` is empty or falsey
     * `-Infinity` is returned. If an iteratee function is provided it is invoked
     * for each value in `collection` to generate the criterion by which the value
     * is ranked. The `iteratee` is bound to `thisArg` and invoked with three
     * arguments: (value, index, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Math
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the maximum value.
     * @example
     *
     * _.max([4, 2, 8, 6]);
     * // => 8
     *
     * _.max([]);
     * // => -Infinity
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * _.max(users, function(chr) {
     *   return chr.age;
     * });
     * // => { 'user': 'fred', 'age': 40 }
     *
     * // using the `_.property` callback shorthand
     * _.max(users, 'age');
     * // => { 'user': 'fred', 'age': 40 }
     */
    var max = createExtremum(gt, NEGATIVE_INFINITY);

    /**
     * Gets the minimum value of `collection`. If `collection` is empty or falsey
     * `Infinity` is returned. If an iteratee function is provided it is invoked
     * for each value in `collection` to generate the criterion by which the value
     * is ranked. The `iteratee` is bound to `thisArg` and invoked with three
     * arguments: (value, index, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Math
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the minimum value.
     * @example
     *
     * _.min([4, 2, 8, 6]);
     * // => 2
     *
     * _.min([]);
     * // => Infinity
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * _.min(users, function(chr) {
     *   return chr.age;
     * });
     * // => { 'user': 'barney', 'age': 36 }
     *
     * // using the `_.property` callback shorthand
     * _.min(users, 'age');
     * // => { 'user': 'barney', 'age': 36 }
     */
    var min = createExtremum(lt, POSITIVE_INFINITY);

    /**
     * Gets the sum of the values in `collection`.
     *
     * @static
     * @memberOf _
     * @category Math
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {number} Returns the sum.
     * @example
     *
     * _.sum([4, 6]);
     * // => 10
     *
     * _.sum({ 'a': 4, 'b': 6 });
     * // => 10
     *
     * var objects = [
     *   { 'n': 4 },
     *   { 'n': 6 }
     * ];
     *
     * _.sum(objects, function(object) {
     *   return object.n;
     * });
     * // => 10
     *
     * // using the `_.property` callback shorthand
     * _.sum(objects, 'n');
     * // => 10
     */
    function sum(collection, iteratee, thisArg) {
      if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
        iteratee = null;
      }
      var callback = getCallback(),
          noIteratee = iteratee == null;

      if (!(noIteratee && callback === baseCallback)) {
        noIteratee = false;
        iteratee = callback(iteratee, thisArg, 3);
      }
      return noIteratee
        ? arraySum(isArray(collection) ? collection : toIterable(collection))
        : baseSum(collection, iteratee);
    }

    /*------------------------------------------------------------------------*/

    // Ensure wrappers are instances of `baseLodash`.
    lodash.prototype = baseLodash.prototype;

    LodashWrapper.prototype = baseCreate(baseLodash.prototype);
    LodashWrapper.prototype.constructor = LodashWrapper;

    LazyWrapper.prototype = baseCreate(baseLodash.prototype);
    LazyWrapper.prototype.constructor = LazyWrapper;

    // Add functions to the `Map` cache.
    MapCache.prototype['delete'] = mapDelete;
    MapCache.prototype.get = mapGet;
    MapCache.prototype.has = mapHas;
    MapCache.prototype.set = mapSet;

    // Add functions to the `Set` cache.
    SetCache.prototype.push = cachePush;

    // Assign cache to `_.memoize`.
    memoize.Cache = MapCache;

    // Add functions that return wrapped values when chaining.
    lodash.after = after;
    lodash.ary = ary;
    lodash.assign = assign;
    lodash.at = at;
    lodash.before = before;
    lodash.bind = bind;
    lodash.bindAll = bindAll;
    lodash.bindKey = bindKey;
    lodash.callback = callback;
    lodash.chain = chain;
    lodash.chunk = chunk;
    lodash.compact = compact;
    lodash.constant = constant;
    lodash.countBy = countBy;
    lodash.create = create;
    lodash.curry = curry;
    lodash.curryRight = curryRight;
    lodash.debounce = debounce;
    lodash.defaults = defaults;
    lodash.defer = defer;
    lodash.delay = delay;
    lodash.difference = difference;
    lodash.drop = drop;
    lodash.dropRight = dropRight;
    lodash.dropRightWhile = dropRightWhile;
    lodash.dropWhile = dropWhile;
    lodash.fill = fill;
    lodash.filter = filter;
    lodash.flatten = flatten;
    lodash.flattenDeep = flattenDeep;
    lodash.flow = flow;
    lodash.flowRight = flowRight;
    lodash.forEach = forEach;
    lodash.forEachRight = forEachRight;
    lodash.forIn = forIn;
    lodash.forInRight = forInRight;
    lodash.forOwn = forOwn;
    lodash.forOwnRight = forOwnRight;
    lodash.functions = functions;
    lodash.groupBy = groupBy;
    lodash.indexBy = indexBy;
    lodash.initial = initial;
    lodash.intersection = intersection;
    lodash.invert = invert;
    lodash.invoke = invoke;
    lodash.keys = keys;
    lodash.keysIn = keysIn;
    lodash.map = map;
    lodash.mapKeys = mapKeys;
    lodash.mapValues = mapValues;
    lodash.matches = matches;
    lodash.matchesProperty = matchesProperty;
    lodash.memoize = memoize;
    lodash.merge = merge;
    lodash.method = method;
    lodash.methodOf = methodOf;
    lodash.mixin = mixin;
    lodash.negate = negate;
    lodash.omit = omit;
    lodash.once = once;
    lodash.pairs = pairs;
    lodash.partial = partial;
    lodash.partialRight = partialRight;
    lodash.partition = partition;
    lodash.pick = pick;
    lodash.pluck = pluck;
    lodash.property = property;
    lodash.propertyOf = propertyOf;
    lodash.pull = pull;
    lodash.pullAt = pullAt;
    lodash.range = range;
    lodash.rearg = rearg;
    lodash.reject = reject;
    lodash.remove = remove;
    lodash.rest = rest;
    lodash.restParam = restParam;
    lodash.set = set;
    lodash.shuffle = shuffle;
    lodash.slice = slice;
    lodash.sortBy = sortBy;
    lodash.sortByAll = sortByAll;
    lodash.sortByOrder = sortByOrder;
    lodash.spread = spread;
    lodash.take = take;
    lodash.takeRight = takeRight;
    lodash.takeRightWhile = takeRightWhile;
    lodash.takeWhile = takeWhile;
    lodash.tap = tap;
    lodash.throttle = throttle;
    lodash.thru = thru;
    lodash.times = times;
    lodash.toArray = toArray;
    lodash.toPlainObject = toPlainObject;
    lodash.transform = transform;
    lodash.union = union;
    lodash.uniq = uniq;
    lodash.unzip = unzip;
    lodash.unzipWith = unzipWith;
    lodash.values = values;
    lodash.valuesIn = valuesIn;
    lodash.where = where;
    lodash.without = without;
    lodash.wrap = wrap;
    lodash.xor = xor;
    lodash.zip = zip;
    lodash.zipObject = zipObject;
    lodash.zipWith = zipWith;

    // Add aliases.
    lodash.backflow = flowRight;
    lodash.collect = map;
    lodash.compose = flowRight;
    lodash.each = forEach;
    lodash.eachRight = forEachRight;
    lodash.extend = assign;
    lodash.iteratee = callback;
    lodash.methods = functions;
    lodash.object = zipObject;
    lodash.select = filter;
    lodash.tail = rest;
    lodash.unique = uniq;

    // Add functions to `lodash.prototype`.
    mixin(lodash, lodash);

    /*------------------------------------------------------------------------*/

    // Add functions that return unwrapped values when chaining.
    lodash.add = add;
    lodash.attempt = attempt;
    lodash.camelCase = camelCase;
    lodash.capitalize = capitalize;
    lodash.clone = clone;
    lodash.cloneDeep = cloneDeep;
    lodash.deburr = deburr;
    lodash.endsWith = endsWith;
    lodash.escape = escape;
    lodash.escapeRegExp = escapeRegExp;
    lodash.every = every;
    lodash.find = find;
    lodash.findIndex = findIndex;
    lodash.findKey = findKey;
    lodash.findLast = findLast;
    lodash.findLastIndex = findLastIndex;
    lodash.findLastKey = findLastKey;
    lodash.findWhere = findWhere;
    lodash.first = first;
    lodash.get = get;
    lodash.gt = gt;
    lodash.gte = gte;
    lodash.has = has;
    lodash.identity = identity;
    lodash.includes = includes;
    lodash.indexOf = indexOf;
    lodash.inRange = inRange;
    lodash.isArguments = isArguments;
    lodash.isArray = isArray;
    lodash.isBoolean = isBoolean;
    lodash.isDate = isDate;
    lodash.isElement = isElement;
    lodash.isEmpty = isEmpty;
    lodash.isEqual = isEqual;
    lodash.isError = isError;
    lodash.isFinite = isFinite;
    lodash.isFunction = isFunction;
    lodash.isMatch = isMatch;
    lodash.isNaN = isNaN;
    lodash.isNative = isNative;
    lodash.isNull = isNull;
    lodash.isNumber = isNumber;
    lodash.isObject = isObject;
    lodash.isPlainObject = isPlainObject;
    lodash.isRegExp = isRegExp;
    lodash.isString = isString;
    lodash.isTypedArray = isTypedArray;
    lodash.isUndefined = isUndefined;
    lodash.kebabCase = kebabCase;
    lodash.last = last;
    lodash.lastIndexOf = lastIndexOf;
    lodash.lt = lt;
    lodash.lte = lte;
    lodash.max = max;
    lodash.min = min;
    lodash.noConflict = noConflict;
    lodash.noop = noop;
    lodash.now = now;
    lodash.pad = pad;
    lodash.padLeft = padLeft;
    lodash.padRight = padRight;
    lodash.parseInt = parseInt;
    lodash.random = random;
    lodash.reduce = reduce;
    lodash.reduceRight = reduceRight;
    lodash.repeat = repeat;
    lodash.result = result;
    lodash.runInContext = runInContext;
    lodash.size = size;
    lodash.snakeCase = snakeCase;
    lodash.some = some;
    lodash.sortedIndex = sortedIndex;
    lodash.sortedLastIndex = sortedLastIndex;
    lodash.startCase = startCase;
    lodash.startsWith = startsWith;
    lodash.sum = sum;
    lodash.template = template;
    lodash.trim = trim;
    lodash.trimLeft = trimLeft;
    lodash.trimRight = trimRight;
    lodash.trunc = trunc;
    lodash.unescape = unescape;
    lodash.uniqueId = uniqueId;
    lodash.words = words;

    // Add aliases.
    lodash.all = every;
    lodash.any = some;
    lodash.contains = includes;
    lodash.eq = isEqual;
    lodash.detect = find;
    lodash.foldl = reduce;
    lodash.foldr = reduceRight;
    lodash.head = first;
    lodash.include = includes;
    lodash.inject = reduce;

    mixin(lodash, (function() {
      var source = {};
      baseForOwn(lodash, function(func, methodName) {
        if (!lodash.prototype[methodName]) {
          source[methodName] = func;
        }
      });
      return source;
    }()), false);

    /*------------------------------------------------------------------------*/

    // Add functions capable of returning wrapped and unwrapped values when chaining.
    lodash.sample = sample;

    lodash.prototype.sample = function(n) {
      if (!this.__chain__ && n == null) {
        return sample(this.value());
      }
      return this.thru(function(value) {
        return sample(value, n);
      });
    };

    /*------------------------------------------------------------------------*/

    /**
     * The semantic version number.
     *
     * @static
     * @memberOf _
     * @type string
     */
    lodash.VERSION = VERSION;

    // Assign default placeholders.
    arrayEach(['bind', 'bindKey', 'curry', 'curryRight', 'partial', 'partialRight'], function(methodName) {
      lodash[methodName].placeholder = lodash;
    });

    // Add `LazyWrapper` methods that accept an `iteratee` value.
    arrayEach(['dropWhile', 'filter', 'map', 'takeWhile'], function(methodName, type) {
      var isFilter = type != LAZY_MAP_FLAG,
          isDropWhile = type == LAZY_DROP_WHILE_FLAG;

      LazyWrapper.prototype[methodName] = function(iteratee, thisArg) {
        var filtered = this.__filtered__,
            result = (filtered && isDropWhile) ? new LazyWrapper(this) : this.clone(),
            iteratees = result.__iteratees__ || (result.__iteratees__ = []);

        iteratees.push({
          'done': false,
          'count': 0,
          'index': 0,
          'iteratee': getCallback(iteratee, thisArg, 1),
          'limit': -1,
          'type': type
        });

        result.__filtered__ = filtered || isFilter;
        return result;
      };
    });

    // Add `LazyWrapper` methods for `_.drop` and `_.take` variants.
    arrayEach(['drop', 'take'], function(methodName, index) {
      var whileName = methodName + 'While';

      LazyWrapper.prototype[methodName] = function(n) {
        var filtered = this.__filtered__,
            result = (filtered && !index) ? this.dropWhile() : this.clone();

        n = n == null ? 1 : nativeMax(floor(n) || 0, 0);
        if (filtered) {
          if (index) {
            result.__takeCount__ = nativeMin(result.__takeCount__, n);
          } else {
            last(result.__iteratees__).limit = n;
          }
        } else {
          var views = result.__views__ || (result.__views__ = []);
          views.push({ 'size': n, 'type': methodName + (result.__dir__ < 0 ? 'Right' : '') });
        }
        return result;
      };

      LazyWrapper.prototype[methodName + 'Right'] = function(n) {
        return this.reverse()[methodName](n).reverse();
      };

      LazyWrapper.prototype[methodName + 'RightWhile'] = function(predicate, thisArg) {
        return this.reverse()[whileName](predicate, thisArg).reverse();
      };
    });

    // Add `LazyWrapper` methods for `_.first` and `_.last`.
    arrayEach(['first', 'last'], function(methodName, index) {
      var takeName = 'take' + (index ? 'Right' : '');

      LazyWrapper.prototype[methodName] = function() {
        return this[takeName](1).value()[0];
      };
    });

    // Add `LazyWrapper` methods for `_.initial` and `_.rest`.
    arrayEach(['initial', 'rest'], function(methodName, index) {
      var dropName = 'drop' + (index ? '' : 'Right');

      LazyWrapper.prototype[methodName] = function() {
        return this[dropName](1);
      };
    });

    // Add `LazyWrapper` methods for `_.pluck` and `_.where`.
    arrayEach(['pluck', 'where'], function(methodName, index) {
      var operationName = index ? 'filter' : 'map',
          createCallback = index ? baseMatches : property;

      LazyWrapper.prototype[methodName] = function(value) {
        return this[operationName](createCallback(value));
      };
    });

    LazyWrapper.prototype.compact = function() {
      return this.filter(identity);
    };

    LazyWrapper.prototype.reject = function(predicate, thisArg) {
      predicate = getCallback(predicate, thisArg, 1);
      return this.filter(function(value) {
        return !predicate(value);
      });
    };

    LazyWrapper.prototype.slice = function(start, end) {
      start = start == null ? 0 : (+start || 0);

      var result = this;
      if (start < 0) {
        result = this.takeRight(-start);
      } else if (start) {
        result = this.drop(start);
      }
      if (end !== undefined) {
        end = (+end || 0);
        result = end < 0 ? result.dropRight(-end) : result.take(end - start);
      }
      return result;
    };

    LazyWrapper.prototype.toArray = function() {
      return this.drop(0);
    };

    // Add `LazyWrapper` methods to `lodash.prototype`.
    baseForOwn(LazyWrapper.prototype, function(func, methodName) {
      var lodashFunc = lodash[methodName];
      if (!lodashFunc) {
        return;
      }
      var checkIteratee = /^(?:filter|map|reject)|While$/.test(methodName),
          retUnwrapped = /^(?:first|last)$/.test(methodName);

      lodash.prototype[methodName] = function() {
        var args = arguments,
            chainAll = this.__chain__,
            value = this.__wrapped__,
            isHybrid = !!this.__actions__.length,
            isLazy = value instanceof LazyWrapper,
            iteratee = args[0],
            useLazy = isLazy || isArray(value);

        if (useLazy && checkIteratee && typeof iteratee == 'function' && iteratee.length != 1) {
          // avoid lazy use if the iteratee has a "length" value other than `1`
          isLazy = useLazy = false;
        }
        var onlyLazy = isLazy && !isHybrid;
        if (retUnwrapped && !chainAll) {
          return onlyLazy
            ? func.call(value)
            : lodashFunc.call(lodash, this.value());
        }
        var interceptor = function(value) {
          var otherArgs = [value];
          push.apply(otherArgs, args);
          return lodashFunc.apply(lodash, otherArgs);
        };
        if (useLazy) {
          var wrapper = onlyLazy ? value : new LazyWrapper(this),
              result = func.apply(wrapper, args);

          if (!retUnwrapped && (isHybrid || result.__actions__)) {
            var actions = result.__actions__ || (result.__actions__ = []);
            actions.push({ 'func': thru, 'args': [interceptor], 'thisArg': lodash });
          }
          return new LodashWrapper(result, chainAll);
        }
        return this.thru(interceptor);
      };
    });

    // Add `Array` and `String` methods to `lodash.prototype`.
    arrayEach(['concat', 'join', 'pop', 'push', 'replace', 'shift', 'sort', 'splice', 'split', 'unshift'], function(methodName) {
      var func = (/^(?:replace|split)$/.test(methodName) ? stringProto : arrayProto)[methodName],
          chainName = /^(?:push|sort|unshift)$/.test(methodName) ? 'tap' : 'thru',
          retUnwrapped = /^(?:join|pop|replace|shift)$/.test(methodName);

      lodash.prototype[methodName] = function() {
        var args = arguments;
        if (retUnwrapped && !this.__chain__) {
          return func.apply(this.value(), args);
        }
        return this[chainName](function(value) {
          return func.apply(value, args);
        });
      };
    });

    // Map minified function names to their real names.
    baseForOwn(LazyWrapper.prototype, function(func, methodName) {
      var lodashFunc = lodash[methodName];
      if (lodashFunc) {
        var key = lodashFunc.name,
            names = realNames[key] || (realNames[key] = []);

        names.push({ 'name': methodName, 'func': lodashFunc });
      }
    });

    realNames[createHybridWrapper(null, BIND_KEY_FLAG).name] = [{ 'name': 'wrapper', 'func': null }];

    // Add functions to the lazy wrapper.
    LazyWrapper.prototype.clone = lazyClone;
    LazyWrapper.prototype.reverse = lazyReverse;
    LazyWrapper.prototype.value = lazyValue;

    // Add chaining functions to the `lodash` wrapper.
    lodash.prototype.chain = wrapperChain;
    lodash.prototype.commit = wrapperCommit;
    lodash.prototype.plant = wrapperPlant;
    lodash.prototype.reverse = wrapperReverse;
    lodash.prototype.toString = wrapperToString;
    lodash.prototype.run = lodash.prototype.toJSON = lodash.prototype.valueOf = lodash.prototype.value = wrapperValue;

    // Add function aliases to the `lodash` wrapper.
    lodash.prototype.collect = lodash.prototype.map;
    lodash.prototype.head = lodash.prototype.first;
    lodash.prototype.select = lodash.prototype.filter;
    lodash.prototype.tail = lodash.prototype.rest;

    return lodash;
  }

  /*--------------------------------------------------------------------------*/

  // Export lodash.
  var _ = runInContext();

  // Some AMD build optimizers like r.js check for condition patterns like the following:
  if (typeof define == 'function' && typeof define.amd == 'object' && define.amd) {
    // Expose lodash to the global object when an AMD loader is present to avoid
    // errors in cases where lodash is loaded by a script tag and not intended
    // as an AMD module. See http://requirejs.org/docs/errors.html#mismatch for
    // more details.
    root._ = _;

    // Define as an anonymous module so, through path mapping, it can be
    // referenced as the "underscore" module.
    define(function() {
      return _;
    });
  }
  // Check for `exports` after `define` in case a build optimizer adds an `exports` object.
  else if (freeExports && freeModule) {
    // Export for Node.js or RingoJS.
    if (moduleExports) {
      (freeModule.exports = _)._ = _;
    }
    // Export for Rhino with CommonJS support.
    else {
      freeExports._ = _;
    }
  }
  else {
    // Export for a browser or Rhino.
    root._ = _;
  }
}.call(this));

}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{}],2:[function(require,module,exports){
var _     = require('lodash');
var proto = {}; // Our soon-to-be prototype shorthand

function DSSEvent(params) {
  this.el = params.el;
  this.type = params.type || '';
  this.time = params.time || 0;
  this.styles = this.omitExtraneousKeys(params.styles || window.getComputedStyle(params.el));
  this.delta;
}

proto.omitExtraneousKeys = function(obj) {
  return _.omit(obj, function(v, k) {
    return !isNaN(parseInt(k)) || k === 'cssText';
  })
}

proto.calcStyleDelta = function(prevStyles) {
  return _.omit(this.styles, function(v, k) {
    return prevStyles[k] === v;
  });
}

DSSEvent.prototype = proto;
module.exports = DSSEvent;

},{"lodash":1}],3:[function(require,module,exports){
var _        = require('lodash');
var DSSEvent = require('./dss_event.js');
var proto    = {};

function DSSEventCollection() {
}

proto.dssEvents = [];

proto.push = function(dssEvent) {
  this.dssEvents.push(dssEvent);
}

proto.fetchByElement = function(el) {
  return _.filter(this.dssEvents, function(dssEvent) {
    return dssEvent.el === el;
  });
}

proto.fetchByTime = function() {
  return _.sortBy(this.dssEvents, 'time');
}

proto.fetchUniqueElements = function() {
  return _.chain(this.dssEvents).uniq(function(dssEvent) {
    return dssEvent.el;
  }).pluck('el').value();
}

proto.createElementGroupings = function() {
  var els = this.fetchUniqueElements();
  return els.map(function(el, i) {
    return {
      el: el,
      events: this.fetchByElement(el)
    };
  }, this);
}

proto.groupedByElement = function() {
  var groupings = this.createElementGroupings();
  // Prepend an empty event with the default styles
  // to calculate the delta from index 0..1
  return groupings.map(function(group) {
    group.events.unshift(new DSSEvent({el: group.el}));
    return group;
  })
}

proto.calculateDeltas = function() {
  this.groupedByElement().forEach(function(group) {
    group.events.forEach(function(dssEvent, i) {
      if(i === 0) return;
      dssEvent.delta = dssEvent.calcStyleDelta(group.events[i-1].styles);
    });
  });
}

proto.fetchDeltas = function() {
  this.calculateDeltas();
  return _.filter(this.fetchByTime(), function(evt) {
    return _.keys(evt.delta).length;
  });
}

DSSEventCollection.prototype = proto;
module.exports = DSSEventCollection;

},{"./dss_event.js":2,"lodash":1}],4:[function(require,module,exports){
var _        = require('lodash');
var DSS      = DSS || {};
var DSSEvent = require('./dss_event.js');
var DSSEventCollection = require('./dss_event_collection.js');

/* --------------------- Constants --------------------- */
DSS.WATCH_EVENTS = ['click', 'mouseover', 'mouseout', 'mousemove', 'scroll', 'transitionend'];
DSS.THROTTLE_LIMIT = 300;

/* --------------------- Variables --------------------- */
DSS.eventCollection = new DSSEventCollection();
DSS.startTime;

/* --------------------- Methods --------------------- */
DSS.record = function record() {
  DSS.WATCH_EVENTS.forEach(function(evt) {
    document.addEventListener(evt, DSS.eventHandler);
  });

  DSS.startTime = Date.now();
}

DSS.stop = function stop() {
  DSS.WATCH_EVENTS.forEach(function(evt) {
    document.removeEventListener(evt, DSS.eventHandler);
  });
}

DSS.eventHandler = _.throttle(function eventHandler(e) {
  var computed = window.getComputedStyle(e.target);
  var dssEvent = new DSSEvent({
    type: e.type,
    time: Date.now() - DSS.startTime,
    styles: computed,
    el: e.target
  });
  DSS.eventCollection.push(dssEvent);
}, DSS.THROTTLE_LIMIT);

/* -----------------------------------------------------
 * Handle messages from the background script
 * -----------------------------------------------------*/
chrome.runtime.onMessage.addListener(function(message, sender, response) {
  switch(message.data) {
    case 'recording:start':
      DSS.record();
      response({data: 'recording:started'});
      break;
    case 'recording:stop':
      DSS.stop();
      response({data: 'recording:stopped'});
      break;
  }
});

},{"./dss_event.js":2,"./dss_event_collection.js":3,"lodash":1}]},{},[4]);