EvEmitter

Lil' event emitter — add a little pub/sub

EvEmitter adds publish/subscribe pattern to a browser class. It's a smaller version of Olical/EventEmitter. That EventEmitter is full featured, widely used, and great. This EvEmitter has just the base event functionality to power the event API in libraries like Isotope, Flickity, Masonry, and imagesLoaded.

API

// class inheritence
class MyClass extends EvEmitter {}

// mixin prototype
Object.assign( MyClass.prototype, EvEmitter.prototype );

// single instance
let emitter = new EvEmitter();

on

Add an event listener.

emitter.on( eventName, listener )

• eventName - String - name of the event
• listener - Function

off

Remove an event listener.

emitter.off( eventName, listener )

once

Add an event listener to be triggered only once.

emitter.once( eventName, listener )

emitEvent

Trigger an event.

emitter.emitEvent( eventName, args )

• eventName - String - name of the event
• args - Array - arguments passed to listeners

allOff

Removes all event listeners.

emitter.allOff()

Code example

// create event emitter
var emitter = new EvEmitter();

// listeners
function hey( a, b, c ) {
  console.log( 'Hey', a, b, c )
}

function ho( a, b, c ) {
  console.log( 'Ho', a, b, c )
}

function letsGo( a, b, c ) {
  console.log( 'Lets go', a, b, c )
}

// bind listeners
emitter.on( 'rock', hey )
emitter.on( 'rock', ho )
// trigger letsGo once
emitter.once( 'rock', letsGo )

// emit event
emitter.emitEvent( 'rock', [ 1, 2, 3 ] )
// => 'Hey', 1, 2, 3
// => 'Ho', 1, 2, 3
// => 'Lets go', 1, 2, 3

// unbind
emitter.off( 'rock', ho )

emitter.emitEvent( 'rock', [ 4, 5, 6 ] )
// => 'Hey' 4, 5, 6

Browser support

EvEmitter v2 uses ES6 features like for...of loops and class definition as such it supports Chrome 49+, Firefox 45+, Safari 9+, and Edge 13+.

For older browser support, use EvEmitter v1.

License

EvEmitter is released under the MIT License. Have at it.