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PR-URL: https://github.com/nodejs/io.js/pull/2286 Reviewed-By: Roman Reiss <me@silverwind.io>
72 lines
2.1 KiB
Markdown
72 lines
2.1 KiB
Markdown
# es6-symbol
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## ECMAScript 6 Symbol polyfill
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For more information about symbols see following links
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- [Symbols in ECMAScript 6 by Axel Rauschmayer](http://www.2ality.com/2014/12/es6-symbols.html)
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- [MDN Documentation](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol)
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- [Specification](http://people.mozilla.org/~jorendorff/es6-draft.html#sec-symbol-constructor)
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### Limitations
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Underneath it uses real string property names which can easily be retrieved, however accidental collision with other property names is unlikely.
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### Usage
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It’s safest to use *es6-symbol* as a [ponyfill](http://kikobeats.com/polyfill-ponyfill-and-prollyfill/) – a polyfill which doesn’t touch global objects:
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```javascript
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var Symbol = require('es6-symbol');
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```
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If you want to make sure your environment implements `Symbol` globally, do:
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```javascript
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require('es6-symbol/implement');
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```
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If you strictly want to use polyfill even if native `Symbol` exists (hard to find a good reason for that), do:
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```javascript
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var Symbol = require('es6-symbol/polyfill');
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```
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#### API
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Best is to refer to [specification](http://people.mozilla.org/~jorendorff/es6-draft.html#sec-symbol-objects). Still if you want quick look, follow examples:
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```javascript
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var Symbol = require('es6-symbol');
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var symbol = Symbol('My custom symbol');
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var x = {};
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x[symbol] = 'foo';
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console.log(x[symbol]); 'foo'
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// Detect iterable:
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var iterator, result;
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if (possiblyIterable[Symbol.iterator]) {
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iterator = possiblyIterable[Symbol.iterator]();
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result = iterator.next();
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while(!result.done) {
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console.log(result.value);
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result = iterator.next();
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}
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}
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```
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### Installation
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#### NPM
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In your project path:
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$ npm install es6-symbol
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##### Browser
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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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## Tests [](https://travis-ci.org/medikoo/es6-symbol)
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$ npm test
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