Readme.md

Emitter

Event emitter component.

Installation

$ component install component/emitter

API

Emitter(obj)

The Emitter may also be used as a mixin. For example a "plain" object may become an emitter, or you may extend an existing prototype:

var obj = {};
Emitter(obj);
Emitter(User.prototype);

Warning: if you use Emitter(Some.prototype) on a prototype you must invoke Emitter.call(this) in the constructor to clear the callbacks object, otherwise events will be shared between multiple objects.

Emitter#on(event, fn)

Register an event handler fn.

Emitter#once(event, fn)

Register a single-shot event handler fn, removed immediately after it is invoked the first time.

Emitter#off(event, fn)

Remove event handler fn, or pass only the event name to remove all handlers for event.

Emitter#emit(event, ...)

Emit an event with variable option args.

Emitter#listeners(event)

Return an array of callbacks, or an empty array.

Emitter#hasListeners(event)

Check if this emitter has event handlers.