| <a href="http://promises-aplus.github.com/promises-spec"> |
| <img src="http://promises-aplus.github.com/promises-spec/assets/logo-small.png" |
| align="right" alt="Promises/A+ logo" /> |
| </a> |
| # Promise Polyfill |
| [![travis][travis-image]][travis-url] |
| |
| [travis-image]: https://img.shields.io/travis/taylorhakes/promise-polyfill.svg?style=flat |
| [travis-url]: https://travis-ci.org/taylorhakes/promise-polyfill |
| |
| |
| Lightweight ES6 Promise polyfill for the browser and node. Adheres closely to the spec. It is a perfect polyfill IE, Firefox or any other browser that does not support native promises. |
| |
| For API information about Promises, please check out this article [HTML5Rocks article](http://www.html5rocks.com/en/tutorials/es6/promises/). |
| |
| It is extremely lightweight. ***< 1kb Gzipped*** |
| |
| ## Browser Support |
| IE8+, Chrome, Firefox, IOS 4+, Safari 5+, Opera |
| |
| ### NPM Use |
| ``` |
| npm install promise-polyfill --save-exact |
| ``` |
| ### Bower Use |
| ``` |
| bower install promise-polyfill |
| ``` |
| |
| ## Downloads |
| |
| - [Promise](https://raw.github.com/taylorhakes/promise-polyfill/master/promise.js) |
| - [Promise-min](https://raw.github.com/taylorhakes/promise-polyfill/master/promise.min.js) |
| |
| ## Simple use |
| ```js |
| import Promise from 'promise-polyfill'; |
| |
| // To add to window |
| if (!window.Promise) { |
| window.Promise = Promise; |
| } |
| ``` |
| |
| then you can use like normal Promises |
| ```js |
| var prom = new Promise(function(resolve, reject) { |
| // do a thing, possibly async, then… |
| |
| if (/* everything turned out fine */) { |
| resolve("Stuff worked!"); |
| } else { |
| reject(new Error("It broke")); |
| } |
| }); |
| |
| prom.then(function(result) { |
| // Do something when async done |
| }); |
| ``` |
| |
| ## Deprecations |
| - `Promise._setImmediateFn(<immediateFn>)` has been deprecated. Use `Promise._immediateFn = <immediateFn>;` instead. |
| - `Promise._setUnhandledRejectionFn(<rejectionFn>)` has been deprecated. Use `Promise._unhandledRejectionFn = <rejectionFn>` instead. |
| These functions will be removed in the next major version. |
| |
| ## Performance |
| By default promise-polyfill uses `setImmediate`, but falls back to `setTimeout` for executing asynchronously. If a browser does not support `setImmediate` (IE/Edge are the only browsers with setImmediate), you may see performance issues. |
| Use a `setImmediate` polyfill to fix this issue. [setAsap](https://github.com/taylorhakes/setAsap) or [setImmediate](https://github.com/YuzuJS/setImmediate) work well. |
| |
| If you polyfill `window.setImmediate` or use `Promise._immediateFn = yourImmediateFn` it will be used instead of `window.setTimeout` |
| ``` |
| npm install setasap --save |
| ``` |
| ```js |
| var Promise = require('promise-polyfill'); |
| var setAsap = require('setasap'); |
| Promise._immediateFn = setAsap; |
| ``` |
| |
| ## Unhandled Rejections |
| promise-polyfill will warn you about possibly unhandled rejections. It will show a console warning if a Promise is rejected, but no `.catch` is used. You can turn off this behavior by setting `Promise._setUnhandledRejectionFn(<rejectError>)`. |
| If you would like to disable unhandled rejections. Use a noop like below. |
| ```js |
| Promise._unhandledRejectionFn = function(rejectError) {}; |
| ``` |
| |
| |
| ## Testing |
| ``` |
| npm install |
| npm test |
| ``` |
| |
| ## License |
| MIT |