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ES6 Promise polyfill

This is a polyfill of ES6 Promise. The implementation based on Jake Archibald implementation a subset of rsvp.js. 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 <a href="http://www.html5rocks.com/en/tutorials/es6/promises/">JavaScript Promises HTML5Rocks article</a>.

Notes

The main target: implementation should be conformance with browser's implementations and to be minimal as possible in size. So it's strictly polyfill of ES6 Promise specification and nothing more.

It passes both Promises/A+ test suite and rsvp.js test suite. And as small as 2,6KB min (or 1KB min+gzip).

The polyfill uses setImmediate if available, or fallback to use setTimeout. Use setImmediate polyfill by @YuzuJS to reach better performance.

How to use

Browser

To install:

bower install es6-promise-polyfill

To use:

<script src="bower_components/es6-promise-polyfill/promise.min.js"></script>
<script>
  var promise = new Promise(...);
</script>

Node.js

To install:

npm install es6-promise-polyfill

To use:

var Promise = require('es6-promise-polyfill').Promise;
var promise = new Promise(...);

AMD

To install:

npm install es6-promise-polyfill

To use:

define(['es6-promise-polyfill'], function(Promise) {
  var promise = new Promise(...);
});

Usage in IE<9

catch is a reserved word in IE<9, meaning promise.catch(func) throws a syntax error. To work around this, use a string to access the property:

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

Or use .then instead:

promise.then(undefined, function(err) {
  // ...
});

License

Licensed under the MIT License.