listen

listen.js

Wait for the results of multiple callbacks

Repository: https://github.com/mantoni/listen.js

Install with NPM

npm install listen

Download for browsers

Standalone browser package are here: http://maxantoni.de/listen.js/

However, you may want to use npm and bundle it with your application using Browserify.

Usage

var listen = require('listen');

var listener = listen();

var callbackA = listener();
var callbackB = listener();

/*
 * Do async stuff with callbacks.
 *
 * Callbacks follow the Node.js convention. They expect an error or null as
 * the first argument and an optional value as the second:
 *
 * Fail: callback(new Error('ouch!'));
 * Return: callback(null, 'some return value');
 */

listener.then(function (err, values) {
  /*
   * err    - 1) null if no callback err'd
   *          2) the error of the callback that err'd
   *          3) an error with name ErrorList wrapping multiple errors
   *
   * values - The non-undefined return values from all callbacks in order of
   *          callback creation
   */
});

API

listen()

Creates and returns a new listener function.

listen(values)

Creates and returns a new listener with the given initial values.

listener()

Creates a new callback associated with the listener. Throws if called after then.

listener(name)

Creates a new named callback that provides its value under the given name.

listener(timeout)

Creates a new callback that errs with a TimeoutError if the callback was not invoked within the given timeout.

listener(func)

Creates a new callback that also invokes the given function with (err, value).

listener(name, func)

Combined listener(name) and listener(func).

listener(name, timeout)

Combined listener(name) and listener(timeout).

listener(func, timeout)

Combined listener(func) and listener(timeout).

listener(name, func, timeout)

Combined listener(name), listener(func) and listener(timeout).

listener.then(func)

Invokes the given function once all callbacks where invoked. If none of the callbacks had errors, the first argument is null, otherwise it's an Error. The second argument is the values array in order of callback creation. Can only be called once.

listener.push(value)

Pushes a value to the internal values array. Throws if called after then.

listener.err(error)

Adds an error to the internal error list. Throws if called after then.

Contributing

Here is what you need for development:

• npm install will install all the dev dependencies
• make does all of the following
• make lint lint the code with JSLint
• make test runs all unit tests in Node
• make browser generates a static web page at test/all.html to run the tests in a browser.
• make phantom runs all tests in a the headless Phantom.JS. Make sure you have phantomjs in your path.

To build a browser package containing the merged / minified scripts run make package.