npm install ypromiseES6 Promise Polyfill
====================
Promises allow you to interact with a value that may or may not be available yet.
Getting Started
---------------
This polyfill can be loaded as:
* A script that acts as a polyfill for native promises and adds a global
Promise constructor if the native version is not available
* A Node.js module available in npm
* An AMD module
* As part of the YUI library. See its User Guide
ypromise module to your dependencies
package.json file of your project:
{
"dependencies": {
"ypromise": "git@github.com:yahoo/ypromise"
}
}
`
Install it using npm:
`
$ npm install
`
#### Usage
The ypromise module exports the Promise constructor:
`js
var Promise = require('ypromise');
function asyncFunction() {
return new Promise(function (resolve, reject) {
resolve('Hello world');
});
}
`
Promise API reference
---------------------
$3
`js
new Promise(function (resolve, reject) {});
`
#### resolve(value)
If value is a promise or a thenable, the new promise will adopt its value once
it settles.
#### reject(reason)
Your promise is rejected with reason. For consistency and debugging it is
encouraged that reason is an instance of Error.
$3
#### promise.then(onFulfilled, onRejected)
onFulfilled is called when/if "promise" resolves. onRejected is called
when/if "promise" rejects. Both are optional, if either/both are omitted the
next onFulfilled/onRejected in the chain is called. Both callbacks have a
single parameter, the fulfillment value or rejection reason. then returns a
new promise equivalent to the value you return from onFulfilled/onRejected
after being passed through Promise.resolve. If an error is thrown in the
callback, the returned promise rejects with that error.
#### promise.catch(onRejected)
Sugar for promise.then(undefined, onRejected).
$3
#### Promise.resolve(value)
Always returns a promise. If value is a promise and its constructor is Promise
resolve will return it without modifying it. Otherwise, resolve will return
a new promise that resolves to value.
#### Promise.reject(reason)
Returns a promise rejected with reason. Sugar for new Promise(function (resolve, reject) { reject(value); }).
#### Promise.all(list)
Returns a promise that fulfills when every item in the array fulfills, and
rejects if (and when) any item rejects. Each array item is passed to
Promise.resolve`, so the array can be a mixture of promise-like objects and other