es6-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