# ES6-Promise (subset of [rsvp.js](https://github.com/tildeio/rsvp.js)) [](https://travis-ci.org/stefanpenner/es6-promise) This is a polyfill of the [ES6 Promise](http://www.ecma-international.org/ecma-262/6.0/#sec-promise-constructor). The implementation is a subset of [rsvp.js](https://github.com/tildeio/rsvp.js) extracted by @jakearchibald, if you're wanting extra features and more debugging options, check out the [full library](https://github.com/tildeio/rsvp.js). For API details and how to use promises, see the <a href="http://www.html5rocks.com/en/tutorials/es6/promises/">JavaScript Promises HTML5Rocks article</a>. ## Downloads * [es6-promise 27.86 KB (7.33 KB gzipped)](https://cdn.jsdelivr.net/npm/es6-promise/dist/es6-promise.js) * [es6-promise-auto 27.78 KB (7.3 KB gzipped)](https://cdn.jsdelivr.net/npm/es6-promise/dist/es6-promise.auto.js) - Automatically provides/replaces `Promise` if missing or broken. * [es6-promise-min 6.17 KB (2.4 KB gzipped)](https://cdn.jsdelivr.net/npm/es6-promise/dist/es6-promise.min.js) * [es6-promise-auto-min 6.19 KB (2.4 KB gzipped)](https://cdn.jsdelivr.net/npm/es6-promise/dist/es6-promise.auto.min.js) - Minified version of `es6-promise-auto` above. ## CDN To use via a CDN include this in your html: ```html <!-- Automatically provides/replaces `Promise` if missing or broken. --> <script src="https://cdn.jsdelivr.net/npm/es6-promise@4/dist/es6-promise.js"></script> <script src="https://cdn.jsdelivr.net/npm/es6-promise@4/dist/es6-promise.auto.js"></script> <!-- Minified version of `es6-promise-auto` below. --> <script src="https://cdn.jsdelivr.net/npm/es6-promise@4/dist/es6-promise.min.js"></script> <script src="https://cdn.jsdelivr.net/npm/es6-promise@4/dist/es6-promise.auto.min.js"></script> ``` ## Node.js To install: ```sh yarn add es6-promise ``` or ```sh npm install es6-promise ``` To use: ```js var Promise = require('es6-promise').Promise; ``` ## Usage in IE<9 `catch` and `finally` are reserved keywords in IE<9, meaning `promise.catch(func)` or `promise.finally(func)` throw a syntax error. To work around this, you can use a string to access the property as shown in the following example. However most minifiers will automatically fix this for you, making the resulting code safe for old browsers and production: ```js promise['catch'](function(err) { // ... }); ``` ```js promise['finally'](function() { // ... }); ``` ## Auto-polyfill To polyfill the global environment (either in Node or in the browser via CommonJS) use the following code snippet: ```js require('es6-promise').polyfill(); ``` Alternatively ```js require('es6-promise/auto'); ``` Notice that we don't assign the result of `polyfill()` to any variable. The `polyfill()` method will patch the global environment (in this case to the `Promise` name) when called. ## Building & Testing You will need to have PhantomJS installed globally in order to run the tests. `npm install -g phantomjs` * `npm run build` to build * `npm test` to run tests * `npm start` to run a build watcher, and webserver to test * `npm run test:server` for a testem test runner and watching builder