medikooes6-map
Map collection as specified in ECMAScript6
Warning:
v0.1 version does not ensure O(1) algorithm complexity (but O(n)). This shortcoming will be addressed in v1.0
Usage
It’s safest to use es6-map as a ponyfill – a polyfill which doesn’t touch global objects:
var Map = require('es6-map');
If you want to make sure your environment implements Map globally, do:
require('es6-map/implement');
If you strictly want to use the polyfill even if the native Map exists, do:
var Map = require('es6-map/polyfill');
Installation
$ npm install es6-map
To port it to Browser or any other (non CJS) environment, use your favorite CJS bundler. No favorite yet? Try: Browserify, Webmake or Webpack
API
Best is to refer to specification. Still if you want quick look, follow examples:
var Map = require('es6-map');
var x = {}, y = {}, map = new Map([['raz', 'one'], ['dwa', 'two'], [x, y]]);
map.size; // 3
map.get('raz'); // 'one'
map.get(x); // y
map.has('raz'); // true
map.has(x); // true
map.has('foo'); // false
map.set('trzy', 'three'); // map
map.size // 4
map.get('trzy'); // 'three'
map.has('trzy'); // true
map.has('dwa'); // true
map.delete('dwa'); // true
map.size; // 3
map.forEach(function (value, key) {
// { 'raz', 'one' }, { x, y }, { 'trzy', 'three' } iterated
});
// FF nightly only:
for (value of map) {
// ['raz', 'one'], [x, y], ['trzy', 'three'] iterated
}
var iterator = map.values();
iterator.next(); // { done: false, value: 'one' }
iterator.next(); // { done: false, value: y }
iterator.next(); // { done: false, value: 'three' }
iterator.next(); // { done: true, value: undefined }
map.clear(); // undefined
map.size; // 0
Tests 
$ npm test