EventEmitter.js

Javascript EventEmitter. The best you'll get ^^

This library supports:

• on: multiple events, event namespaces, multiple listeners, listeners with context
• off: all, multiple events, event namespaces, multiple listeners, listeners with context
• emit: multiple events, event namespaces
• listeners: multiple events, namespaces, all at once
• newListener/removeListener events
• chainable
• includes inherit method and noConflict
• amd and node support

Support

Minimum IE 9, Chrome 5, Firefox 4, Opera 10.5, Safari 5, Mobile browsers, Node

For older browser support, a compatible version is added.

Install

• Install with yarn: yarn add opusonline-eventemitter.js

• Install with npm: npm install opusonline-eventemitter.js

Usage

Example

function Foo() {
	EventEmitter.call(this);
}

EventEmitter.inherits(Foo);
// in node you could also use require('util').inherits(Foo, EventEmitter);

Foo.prototype.bar = function() {
	this.emit('bar');
};

var foo = new Foo();
foo.on('bar', function() {
	console.log('Yeah, it works!');
});
foo.bar();

Some Highlights:

var ee = EventEmitter.noConflict(); // no conflict to other EventEmitter implementations

foo.on(['foo', 'bar'], listener1, [listener2, myContext]); // multiple events, multiple listener, listeners context

foo
	.on('newListener', function(event, ee) { // newListener event
		console.log(ee.listener);
	})
	.on('foo.bar', something); // chaining, namespaces

foo.emit(['foo', 'pow'], arg1, arg2); // emit multiple events at once

foo.off('.bar'); // namespaces

Methods

noConflict

var ee = EventEmitter.noConflict();

inherits

Build in inherits method. In node you can use util.inherits(ctor, EventEmitter) instead or the build in method.

function Foo() {
	EventEmitter.call(this);
}
EventEmitter.inherits(Foo);

on (alias: addListener)

var ee = new EventEmitter();
ee.on('go', go); // normal
ee.on(['go', 'foo'], go); // multiple events
ee.on(['go', 'foo'], go, foo); // multiple events, multiple listeners
ee.on('go.now', go); // namespace
ee.on('go.now', go, goFurther); // namespace, multiple listeners
ee.on(['go.now', 'foo'], go, goFurther); // multiple events including namespace, multiple listeners
ee.on('go', [go, person]); // listeners context
ee.on('go', go.bind(person)); // listeners context in native way

once

Includes all possible parameters like on. The event removeListener is called after execution.

var ee = new EventEmitter();
ee.once('go', go);

off (alias: removeListener, removeAllListeners)

var ee = new EventEmitter();
ee.off(); // same as ee.removeAllListeners();
ee.off('go'); // same as ee.removeAllListeners('go');
ee.off('go', go); // same as ee.removeListener('go', go);
ee.off(['go', 'foo'], go); // same listener on multiple events
ee.off('go', go, foo); // multiple listeners
ee.off('go.now', go); // namespace
ee.off('.now', go); // namespace and listener
ee.off('.now'); // all listener from event namespace
ee.off('go', [go, person]); // remove listener with according context

emit

var ee = new EventEmitter();
ee.emit('go', now);
ee.emit('go'); // without arguments
ee.emit('go.now'); // namespace
ee.emit(['go', 'foo'], now); // multiple events

listeners

var ee = new EventEmitter();
ee.listeners(); // all existing listeners
ee.listeners('go'); // normal
ee.listeners('go', 'foo'); // multiple events
ee.listeners('.now'); // namespace

newListener, removeListener events

newListener is always fired after added to list of events. removeListener is always fired before removing from list of events. ee is an object containing listener, context, namespaces, once.

var ee = new EventEmitter();
ee.on('newListener', function(event, ee) {
	console.log(event, ee.listener);
});
ee.on('removeListener', function(event, ee) {
	console.log(event, ee.listener);
});