eventemitter.js

This provides an API like node.js's EventEmitter for the web.

Usage

First, import eventemitter.js using a script tag:

<script src="event_emitter.js"></script>

Next, subclass EventEmitter like this:

function MyClass() {
  window.EventEmitter.call(this);
  // Your initialization here...
}

MyClass.prototype = Object.create(window.EventEmitter.prototype);

If you wish to use multiple inheritance, you can use EventEmitter.makeSubclass(proto) to add the EventEmitter prototype to an existing prototype:

function MyFancyClass() {
  EventEmitter.call(this);
  // Other superclass calls...
  // Your initialization code...
}
MyFancyClass.prototype = Object.create(SomeOtherBaseClass.prototype);
window.EventEmitter.makeSubclass(MyFancyClass.prototype);

An EventEmitter implements the following methods:

• [function] listeners(name) - return all the listeners for an event name.
• void addListener(name, listener) - add a listener for the given event.
• void removeListener(name, listener) - remove a listener, given its name and handler.
• void on(name, listener) - alias for addListener.
• void once(name, listener) - register a listener which will be called once for the event. You will not be able to remove the listener through removeListener.
• void removeAllListeners([name]) - remove all of the listeners. You may supply a name, in which case only listeners for that name will be removed.
• void emit(name, [arguments[, ...]]) - trigger all the listeners for the given name. If you specify arguments, they will be passed to all of the listeners as arguments.