EventEmitter

events~ EventEmitter

NodeJS like EventEmitter. See also NodeJS events documentation

To add event emitting ability to any object:

 var myObject = {},
 //compatibility EventEmitter = require('events').EventEmitter;
 EventEmitter = require('events');
 // add EventEmitter to myObject
 EventEmitter.call(myObject);
 var util = require('util');
 util._extend(myObject, EventEmitter.prototype);

In case object created via constructor function

 function MyObject() {
    EventEmitter.call(this);
 }
 util.inherits(MyObject, EventEmitter);

 var myObject = new MyObject();

Usage:

 myObject.on('myEvent', function(num, str){console.log(num, str) });

 myObject.emit('myEvent', 1, 'two'); // output: 1 two

Methods

setMaxListeners(n)

Obviously not all Emitters should be limited to 10. This function allows that to be increased. Set to zero for unlimited.
Arguments:
  1. n (Number)

getMaxListeners() → Number

emit(type, …eventArgs) → boolean

Execute each of the listeners in order with the supplied arguments. Returns true if event had listeners, false otherwise.
Arguments:
  1. type (String)  Event name
  2. ...eventArgs (*)  Arguments, passed to listeners

addListener(type, listener) → EventEmitter

Adds a listener to the end of the listeners array for the specified event. Will emit newListener event on success.

Usage sample:

 Session.on('login', function () {
     console.log('someone connected!');
 });

Returns emitter, so calls can be chained.

Arguments:
  1. type (String)  Event name
  2. listener (function)

on(type, listener) → EventEmitter

Alias for addListener
Arguments:
  1. type (String)  Event name
  2. listener (function)

once(type, listener) → EventEmitter

Adds a one time listener for the event. This listener is invoked only the next time the event is fired, after which it is removed.
Arguments:
  1. type (String)  Event name
  2. listener (function)

removeListener(type, listener)

Remove a listener from the listener array for the specified event. Caution: changes array indices in the listener array behind the listener. Emits a 'removeListener' event if the listener was removed.
Arguments:
  1. type (String)  Event name
  2. listener (function)

removeAllListeners(type) → EventEmitter

Removes all listeners, or those of the specified event. It's not a good idea to remove listeners that were added elsewhere in the code, especially when it's on an emitter that you didn't create (e.g. sockets or file streams).

Returns emitter, so calls can be chained.

Arguments:
  1. type (String)  Event name

listeners(type) → Array.<function()>

Returns an array of listeners for the specified event.
Arguments:
  1. type (String)  Event name

listenerCount(emitter, type) → Number static

Return the number of listeners for a given event.
Arguments:
  1. emitter (EventEmitter)
  2. type (String)