Package Exports

when
when/apply
when/delay
when/timeout

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (when) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

when.js

A lightweight CommonJS Promises/A and when() implementation. It also provides several other useful Promise-related concepts, such as joining and chaining, and has a robust unit test suite.

It's just over 1k when compiled with Google Closure (w/advanced optimizations) and gzipped.

when.js was derived from the async core of wire.js.

What's New?

1.4.1

Code and unit test cleanup and streamlining--no functional changes.

1.4.0

Create a resolved promise: when.resolve(value) creates a resolved promise for value. See API docs.
Resolve/reject return something useful: deferred.resolve and deferred.reject now return a promise for the fulfilled or rejected value.
Resolve a deferred with another promise: deferred.resolve(promise) - when promise resolves or rejects, so will deferred.

Full Changelog

Docs & Examples

API docs

More info on the wiki

Examples

Quick Start

AMD

git clone https://github.com/cujojs/when or git submodule add https://github.com/cujojs/when

Configure your loader with a package:

packages: [
    { name: 'when', location: 'path/to/when/', main: 'when' },
    // ... other packages ...
]

define(['when', ...], function(when, ...) { ... }); or require(['when', ...], function(when, ...) { ... });

Script Tag

git clone https://github.com/cujojs/when or git submodule add https://github.com/cujojs/when
<script src="path/to/when/when.js"></script>
when will be available as window.when

Node

npm install when
var when = require('when');

RingoJS

ringo-admin install cujojs/when
var when = require('when');

Running the Unit Tests

Install buster.js

npm install -g buster

Run unit tests in Node:

buster test -e node

Run unit tests in Browsers (and Node):

buster server - this will print a url
Point browsers at /capture, e.g. localhost:1111/capture
buster test or buster test -e browser

References

Much of this code was inspired by @unscriptable's tiny promises, the async innards of wire.js, and some gists here, here, here, and here

Some of the code has been influenced by the great work in Q, Dojo's Deferred, and uber.js.