Emitter

Module	ejs
Definition	class Emitter
Inheritance	Emitter Object
Stability	Prototype.
Example	events.on(event, function (event, ...args) { // Do something }).fire("topic", 1, 2, 3) @stability prototype

The emitter class provides a publish/subscribe model of communication via events.

It supports the registration of observers who want to subscribe to events of interest.

Properties

(No own properties defined)

(No own class methods defined)

Qualifiers	Method

Qualifiers	Method
	Emitter()
	Construct a new event Emitter object.
	clearObservers(name: Object = null): Void
	Clear observers for a given event name.
	fire(name: String, args: Array): Void
	Emit an event to the registered observers.
	getObservers(name: String): Array
	Return the observers for this emitter.
	fireThis(name: String, thisObj: Object, args: Array): Void
	Emit an event to the registered observers using an explict value for the "this" object.
	hasObservers(): Boolean
	Determine if the emitter has any observers.
	off(name: Object, callback: Function): Void
	Turn off and remove a registered observer.
	on(name: Object, callback: Function): Emitter
	Add an observer for a set of named event.

Emitter()

clearObservers(name: Object = null): Void

Parameters

name: Object

Event name to clear. The name can be a string or an array of event strings. If null, observers for all event names are cleared. [default: null]

fire(name: String, args: Array): Void

Parameters

name: String	Event name to fire to the observers.
args: Array	Args to pass to the observer callback.

getObservers(name: String): Array

Parameters

name: String

Event name to fire to the observers.

Returns: An array of observer endpoints. These are cloned and not the actual observer objects. 8.

fireThis(name: String, thisObj: Object, args: Array): Void

Description: Emit an event to the registered observers using an explict value for the "this" object.

Parameters

name: String	Event name to fire to the observers.
thisObj: Object	Object to use for "this" when running the callback. This overrides any bound values for "this".
args: Array	Args to pass to the observer callback.

hasObservers(): Boolean

off(name: Object, callback: Function): Void

Parameters

name: Object	Event name used when the observer was added.
callback: Function	Callback function used when the observer was added. If null is supplied, all callbacks will be removed.

on(name: Object, callback: Function): Emitter

Description: Add an observer for a set of named event. The callback will be invoked when the requested event is fired by calling Emitter.fire. When the callback runs, it will be invoked with the value of "this" relevant to the context of the callback. If the callback is a class method, the value of "this" will be the object instance. Global functions will have "this" set to the global object. Use Function.bind to override the bound "this" value.

Parameters

name: Object	Event name to observe. The observer will receive events of this event class or any of its subclasses. The name can be a string or an array of event strings.
callback: Function	Function to call when the event is received.