add support of big data

bases.js

@@ -3,16 +3,19 @@
 // See README.md for details.
 
 var bases = (typeof exports !== 'undefined' ? exports : (window.Bases = {}));
+const Big = require('big.js');
 
 // Returns a string representation of the given number for the given alphabet:
 bases.toAlphabet = function (num, alphabet) {
     var base = alphabet.length;
     var digits = [];    // these will be in reverse order since arrays are stacks
+    num = Big(num);
 
     // execute at least once, even if num is 0, since we should return the '0':
     do {
-        digits.push(num % base);    // TODO handle negatives properly?
-        num = Math.floor(num / base);
+        digits.push(num.mod(base));    // TODO handle negatives properly?
+        num = num.div(base);
+        num = new Big(num).round(0, 0);
     } while (num > 0);
 
     var chars = [];
@@ -24,15 +27,15 @@ bases.toAlphabet = function (num, alphabet) {
 
 // Returns an integer representation of the given string for the given alphabet:
 bases.fromAlphabet = function (str, alphabet) {
-    var base = alphabet.length;
+    var base = new Big(alphabet.length);
     var pos = 0;
-    var num = 0;
+    var num = new Big(0);
     var c;
 
     while (str.length) {
         c = str[str.length - 1];
         str = str.substr(0, str.length - 1);
-        num += Math.pow(base, pos) * alphabet.indexOf(c);
+        num = num.plus(base.pow(pos).times(alphabet.indexOf(c)));
         pos++;
     }
 

package.json

@@ -1,19 +1,28 @@
-{ "name": "bases"
-, "version": "0.2.1"
-, "description": "Utility for converting numbers to/from different bases/alphabets."
-, "author": "Aseem Kishore <[email protected]>"
-, "homepage": "https://github.com/aseemk/bases.js"
-, "keywords": ["alphabet", "base", "base-36", "base-58", "base-62"]
-, "repository":
-  { "type": "git"
-  , "url": "https://github.com/aseemk/bases.js.git"
-  }
-, "main": "bases.js"
-, "dependencies": {}
-, "engines":
-  { "node": "*"
-  }
-, "scripts":
-  { "test": "node test"
+{
+  "name": "bases",
+  "version": "0.2.1",
+  "description": "Utility for converting numbers to/from different bases/alphabets.",
+  "author": "Aseem Kishore <[email protected]>",
+  "homepage": "https://github.com/aseemk/bases.js",
+  "keywords": [
+    "alphabet",
+    "base",
+    "base-36",
+    "base-58",
+    "base-62"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/aseemk/bases.js.git"
+  },
+  "main": "bases.js",
+  "dependencies": {
+    "big.js": "^5.2.2"
+  },
+  "engines": {
+    "node": "*"
+  },
+  "scripts": {
+    "test": "node test"
   }
 }

test.js

@@ -126,5 +126,13 @@ for (var base in DATA) {
     }
 }
 
+const maxMd5Hash = 'ffffffffffffffffffffffffffffffff';
+const number = bases.fromBase(maxMd5Hash, 16);
+const compacted = bases.toBase(number, 62);
+console.log(compacted);
+const backNumber = bases.fromBase(compacted, 62);
+const backHash = bases.toBase(backNumber, 16);
+assert.equal(backHash, maxMd5Hash);
+
 // finally...
 console.log('All tests passed.');