es6-map

ECMAScript6 Map polyfill

es6-map

If you want to make sure your environment implements Map, do:

require('es6-map/implement');

If you'd like to use native version when it exists and fallback to polyfill if it doesn't, but without implementing Map on global scope, do:

var Map = require('es6-map');

If you strictly want to use polyfill even if native Map exists, do:

var Map = require('es6-map/polyfill');
$ 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

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 (valuekey) {
  // { '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