79 lines
2.3 KiB
Markdown
79 lines
2.3 KiB
Markdown
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[![Build status][nix-build-image]][nix-build-url]
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[![Windows status][win-build-image]][win-build-url]
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![Transpilation status][transpilation-image]
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[![npm version][npm-image]][npm-url]
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# es6-weak-map
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## WeakMap collection as specified in ECMAScript6
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_Roughly inspired by Mark Miller's and Kris Kowal's [WeakMap implementation](https://github.com/drses/weak-map)_.
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Differences are:
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- Assumes compliant ES5 environment (no weird ES3 workarounds or hacks)
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- Well modularized CJS style
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- Based on one solution.
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### Limitations
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- Will fail on non extensible objects provided as keys
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### Installation
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$ npm install es6-weak-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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### Usage
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If you want to make sure your environment implements `WeakMap`, do:
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```javascript
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require("es6-weak-map/implement");
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```
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If you'd like to use native version when it exists and fallback to polyfill if it doesn't, but without implementing `WeakMap` on global scope, do:
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```javascript
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var WeakMap = require("es6-weak-map");
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```
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If you strictly want to use polyfill even if native `WeakMap` exists, do:
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```javascript
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var WeakMap = require("es6-weak-map/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-weakmap-objects). Still if you want quick look, follow example:
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```javascript
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var WeakMap = require("es6-weak-map");
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var map = new WeakMap();
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var obj = {};
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map.set(obj, "foo"); // map
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map.get(obj); // 'foo'
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map.has(obj); // true
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map.delete(obj); // true
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map.get(obj); // undefined
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map.has(obj); // false
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map.set(obj, "bar"); // map
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map.has(obj); // false
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```
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## Tests
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$ npm test
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[nix-build-image]: https://semaphoreci.com/api/v1/medikoo-org/es6-weak-map/branches/master/shields_badge.svg
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[nix-build-url]: https://semaphoreci.com/medikoo-org/es6-weak-map
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[win-build-image]: https://ci.appveyor.com/api/projects/status/1c73c57pg4s6lwmu?svg=true
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[win-build-url]: https://ci.appveyor.com/project/medikoo/es6-weak-map
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[transpilation-image]: https://img.shields.io/badge/transpilation-free-brightgreen.svg
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[npm-image]: https://img.shields.io/npm/v/es6-weak-map.svg
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[npm-url]: https://www.npmjs.com/package/es6-weak-map
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