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