event emitter for Javascript

A Javascript event emitter implementation without any dependencies.

API

const EventEmitter = require('@axetroy/event-emitter.js');
const event = new EventEmitter();

const cancelSayHello = event.on('greet', function(name) {
  console.log(`hello ${name}`);
});

const cancelSayHi = event.on('greet', function(name) {
  console.log(`hi ${name}`);
});

event.emit('greet', 'Axetroy');
// hello Axetroy
// hi Axetroy

cancelSayHello();   // remove this listener

event.emit('greet', 'Axetroy');
// hi Axetroy

event.off('greet');

event.emit('greet', 'Axetroy');   // nothing happen

event.on(String event, Function listener(...data))

listen an event, return a Function to remove this listener.

event.once(String event, Function listener(...data))

listen an event only once, it will remove the listener once it trigger

event.off(String event)

remove all listener about this event

event.clear()

clean all listener

event.emit(String event, ...data)

fire an event, without an optional data, data can be multiple arguments

event.emitting(String event, Array dataArray, Function listener)

do not invoke this method in manual.

use this method extend your event emitter

class MyEventEmitter extends EventEmitter {
  emitting(event, dataArray, listener) {
    const start = Date.now();
    listener.apply(this, dataArray);    // the default method is only contain this line
    const time = Date.now() - start;
    console.log('time: ' + time);
  }
}

Test

yarn run test

Contribute

git clone https://github.com/axetroy/event-emitter.js.git
cd ./event-emitter.js
yarn run watch

You can flow Contribute Guide

License

The MIT License