ES6-Promise (subset of rsvp.js)

This is a polyfill of the ES6 Promise. The implementation is a subset of rsvp.js extracted by @jakearchibald, if you're wanting extra features and more debugging options, check out the full library.

For API details and how to use promises, see the JavaScript Promises HTML5Rocks article.

Downloads

• es6-promise 27.86 KB (7.33 KB gzipped)
• es6-promise-auto 27.78 KB (7.3 KB gzipped) - Automatically provides/replaces Promise if missing or broken.
• es6-promise-min 6.17 KB (2.4 KB gzipped)
• es6-promise-auto-min 6.19 KB (2.4 KB gzipped) - Minified version of es6-promise-auto above.

CDN

To use via a CDN include this in your 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:

yarn add es6-promise

or

npm install es6-promise

To use:

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:

promise['catch'](function(err) {
  // ...
});

promise['finally'](function() {
  // ...
});

Auto-polyfill

To polyfill the global environment (either in Node or in the browser via CommonJS) use the following code snippet:

require('es6-promise').polyfill();

Alternatively

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