index.js

'use strict';

var objectAssign = require('object-assign');
var { createPropListMatcher } = require('./src/prop-list-matcher');
var { getUnitRegexp } = require('./src/pixel-unit-regexp');

var defaults = {
  unitToConvert: 'px',
  viewportWidth: 320,
  viewportHeight: 568, // not now used; TODO: need for different units and math for different properties
  unitPrecision: 5,
  viewportUnit: 'vw',
  fontViewportUnit: 'vw',  // vmin is more suitable.
  selectorBlackList: [],
  propList: ['*'],
  minPixelValue: 1,
  mediaQuery: false,
  replace: true,
  landscape: false,
  landscapeUnit: 'vw',
  landscapeWidth: 568
};

var ignoreNextComment = 'px-to-viewport-ignore-next';
var ignorePrevComment = 'px-to-viewport-ignore';

module.exports = function (options) {
  var opts = objectAssign({}, defaults, options);

  checkRegExpOrArray(opts, 'exclude');
  checkRegExpOrArray(opts, 'include');

  var pxRegex = getUnitRegexp(opts.unitToConvert);
  var satisfyPropList = createPropListMatcher(opts.propList);
  var landscapeRules = [];

  return {
    postcssPlugin: 'postcss-px-to-viewport',
    Once (css, { result, AtRule }) {
      css.walkRules(function (rule) {
          // Add exclude option to ignore some files like 'node_modules'
          var file = rule.source && rule.source.input.file;

          if (opts.include && file) {
            if (Object.prototype.toString.call(opts.include) === '[object RegExp]') {
              if (!opts.include.test(file)) return;
            } else if (Object.prototype.toString.call(opts.include) === '[object Array]') {
              var flag = false;
              for (var i = 0; i < opts.include.length; i++) {
                if (opts.include[i].test(file)) {
                  flag = true;
                  break;
                }
              }
              if (!flag) return;
            }
          }
    
          if (opts.exclude && file) {
            if (Object.prototype.toString.call(opts.exclude) === '[object RegExp]') {
              if (opts.exclude.test(file)) return;
            } else if (Object.prototype.toString.call(opts.exclude) === '[object Array]') {
              for (var i = 0; i < opts.exclude.length; i++) {
                if (opts.exclude[i].test(file)) return;
              }
            }
          }
    
          if (blacklistedSelector(opts.selectorBlackList, rule.selector)) return;

          if (opts.landscape && !rule.parent.params) {
            var landscapeRule = rule.clone().removeAll();
    
            rule.walkDecls(function(decl) {
              if (decl.value.indexOf(opts.unitToConvert) === -1) return;
              if (!satisfyPropList(decl.prop)) return;
              landscapeRule.append(decl.clone({
                value: decl.value.replace(pxRegex, createPxReplace(opts, opts.landscapeUnit, opts.landscapeWidth))
              }));
            });
    
            if (landscapeRule.nodes.length > 0) {
              landscapeRules.push(landscapeRule);
            }
          }
    
          if (!validateParams(rule.parent.params, opts.mediaQuery)) return;
    
          rule.walkDecls(function(decl, i) {
            if (decl.value.indexOf(opts.unitToConvert) === -1) return;
            if (!satisfyPropList(decl.prop)) return;
    
            var prev = decl.prev();
            // prev declaration is ignore conversion comment at same line
            if (prev && prev.type === 'comment' && prev.text === ignoreNextComment) {
              // remove comment
              prev.remove();
              return;
            }
            var next = decl.next();
            // next declaration is ignore conversion comment at same line
            if (next && next.type === 'comment' && next.text === ignorePrevComment) {
              if (/\n/.test(next.raws.before)) {
                result.warn('Unexpected comment /* ' + ignorePrevComment + ' */ must be after declaration at same line.', { node: next });
              } else {
                // remove comment
                next.remove();
                return;
              }
            }
    
            var unit;
            var size;
            var params = rule.parent.params;
    
            if (opts.landscape && params && params.indexOf('landscape') !== -1) {
              unit = opts.landscapeUnit;
              size = opts.landscapeWidth;
            } else {
              unit = getUnit(decl.prop, opts);
              size = opts.viewportWidth;
            }
    
            var value = decl.value.replace(pxRegex, createPxReplace(opts, unit, size));
    
            if (declarationExists(decl.parent, decl.prop, value)) return;
    
            if (opts.replace) {
              decl.value = value;
            } else {
              decl.parent.insertAfter(i, decl.clone({ value: value }));
            }
          });
        }
      );

      if (landscapeRules.length > 0) {
        var landscapeRoot = new AtRule({ params: '(orientation: landscape)', name: 'media' });
  
        landscapeRules.forEach(function(rule) {
          landscapeRoot.append(rule);
        });
        css.append(landscapeRoot);
      }
    },
  };
};

module.exports.postcss = true;

function getUnit(prop, opts) {
  return prop.indexOf('font') === -1 ? opts.viewportUnit : opts.fontViewportUnit;
}

function createPxReplace(opts, viewportUnit, viewportSize) {
  return function (m, $1) {
    if (!$1) return m;
    var pixels = parseFloat($1);
    if (pixels <= opts.minPixelValue) return m;
    var parsedVal = toFixed((pixels / viewportSize * 100), opts.unitPrecision);
    return parsedVal === 0 ? '0' : parsedVal + viewportUnit;
  };
}

function checkRegExpOrArray(options, optionName) {
  var option = options[optionName];
  if (!option) return;
  if (Object.prototype.toString.call(option) === '[object RegExp]') return;
  if (Object.prototype.toString.call(option) === '[object Array]') {
    var bad = false;
    for (var i = 0; i < option.length; i++) {
      if (Object.prototype.toString.call(option[i]) !== '[object RegExp]') {
        bad = true;
        break;
      }
    }
    if (!bad) return;
  }
  throw new Error('options.' + optionName + ' should be RegExp or Array of RegExp.');
}

function toFixed(number, precision) {
  var multiplier = Math.pow(10, precision + 1),
    wholeNumber = Math.floor(number * multiplier);
  return Math.round(wholeNumber / 10) * 10 / multiplier;
}

function blacklistedSelector(blacklist, selector) {
  if (typeof selector !== 'string') return;
  return blacklist.some(function (regex) {
    if (typeof regex === 'string') return selector.indexOf(regex) !== -1;
    return selector.match(regex);
  });
}

function declarationExists(decls, prop, value) {
  return decls.some(function (decl) {
      return (decl.prop === prop && decl.value === value);
  });
}

function validateParams(params, mediaQuery) {
  return !params || (params && mediaQuery);
}