Why

Just because simplicity is the ultimate sophistication...
If you need a basic event emitter system, you are in the right place.
For 419 bytes once gzipped, you get on, off and emit methods...
Enjoy !

Let's play !!!

Remove all
listeners
AUTO
Event listeners (Crtl+Click on one toggles all) :

Playing : 

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Left collision : 

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Top collision : 

  | 

Right collision : 

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Bottom collision : 

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Paddle collision : 

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Brick collision : 

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Installation

npm

npm i -D amstramgram-event-emitter

And then in your javascript : 

import EventEmitter from 'Amstramgram-Event-Emitter/Light'

Manually

Just download the source and use it in your project.

import EventEmitter from './src_folder/amstramgramEventEmitterLight'

Usage

Basic

//Basic demo
//Instanciation
const emitter = new EventEmitter()

//Same sillyCallback for two events
emitter.on('firstevent secondevent', sillyCallback)

//stupidCallback
emitter.on('firstevent', stupidCallback)

emitter.on('thirdevent', function(text, eventName){
  console.log(text + eventName + ' !!!')
})

function sillyCallback(e) {
  console.log(e.text, "My nickname is " + e.eventName, e.plus ? "." : "and I'm called by a sillyCallback...")
  if (e.plus) console.log(e.plus)
}

function stupidCallback(e) {
  console.log(e.text, "My nickname is " + e.eventName, "and I'm called by a stupidCallback...")
}

emitter.emit('firstevent', { text: "Hello, I'm the FirstEvent!!!" })
emitter.emit('secondevent', { text: "Hello, I'm the SecondEvent!!!", plus: "Have a nice day !" })
emitter.emit('thirdevent', "Hi, I am the ThirdEvent ans my nickname is ")

emitter.off('firstevent')
emitter.emit('firstevent', { text: "Hello, I'm the FirstEvent but you'll never see me !!!" })

Open your console to see the result...

Note that the event name is always passed as last argument to the callback.

Normal

However, if you really need a event emitter, it is probably for use its features in your own class : 

import EventEmitter from 'Amstramgram-Event-Emitter/Light'

class MyFabulousClass extends EventEmitter {
  ...
  constructor() {
    super()
    ...
    setTimeout(() => {
      this.emit('initialization-end')
    }, 1)
  }
  ...
}
...
const myFabulousClass = new MyFabulousClass()
myFabulousClass.on('initialization-end', _ => {
  console.log("I'm ready !")
  myFabulousClass.off('initialization-end')
})

API

constructor

const emitter = new EventEmitter()

on

/**
 * @description : register a callback for a list of events
 * @param {string} eventsNames : list of event names separated by a space
 * @param {function} callback : function called each time one event of eventsNames is emitted.
 * @returns this so methods can be chained.
**/
emitter.on(eventsNames, callback)

off

/**
 * @description : remove a callback for a list of events.
 * @param {string} eventsNames : list of event names separated by a space.
 * @param {function} callback : callback to removed.
 * @returns this so methods can be chained.
**/
emitter.off(eventsNames, callback)

/**
 * @description : remove all the registered callbacks for a list of events.
 * @param {string} eventsNames : list of event names separated by a space.
 * @returns this so methods can be chained.
**/
emitter.off(eventsNames)

/**
 * @description : remove the callback for all registered events.
 * @param {function} callback : callback to removed.
 * @returns this so methods can be chained.
**/
emitter.off(callback)

/**
 * @description : remove all registered events and callbacks.
 * @returns this so methods can be chained.
**/
emitter.off()

emit

/**
 * @description : emit a given event.
 * @param {String} eventName : event to emit.
 * @param  {...any} args parameters passed to the callbacks.
 *    If args is an object, the property eventName 
 *      with the name of the emitted event is automatically added to it.
 *    In all other cases, the event name is passed as last argument to the callback.
 * @returns this so methods can be chained.
**/
emitter.emit(eventName, args)

events

/**
 * @getter {Set} a Set of all registered events.
**/
console.log(emitter.events)

//Output true if 'myevent' is a registered event, false otherwise
console.log(emitter.events.has('myevent'))

eventsAndCallbacks

/**
 * @getter {Object}
 * Returns an object which contains all the registered events and their callbacks
 * {
 *  eventName01 : set listing the registered callbacks,
 *  ......
 *  eventName0n : set listing the registered callbacks
 * }
**/
console.log(emitter.eventsAndCallbacks)

//Output true if myCallback will be called by 'myevent', false otherwise
console.log(emitter.events.has('myevent') && emitter.eventsAndCallbacks['myevent'].has(myCallback))