Promise [](https://travis-ci.org/taylorhakes/promise-polyfill) =============

Lightweight promise polyfill for the browser and node. A+ Compliant. It is a perfect polyfill IE, Firefox or any other browser that does not support native promises.

This implementation is based on then/promise. It has been changed to use the prototype for performance and memory reasons.

For API information about Promises, please check out this article HTML5Rocks article.

It is extremely lightweight. < 1kb Gzipped

Browser Support

IE8+, Chrome, Firefox, IOS 4+, Safari 5+, Opera

Downloads

• Promise
• Promise-min

Node

npm install promise-polyfill

Bower

bower install promise-polyfill

Simple use

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"));
  }
});

// Do something when async done
prom.then(function() {
  ...
});

Performance

By default promise-polyfill uses setImmediate, but falls back to setTimeout for executing asynchronously. If a browser does not support setImmediate, you may see performance issues. Use a setImmediate polyfill to fix this issue. setAsap or setImmediate work well.

If you polyfill window.setImmediate or define Promise.immediateFn it will be used instead of window.setTimeout

Testing

npm install
npm test

License

MIT