axetroy / event-emitter.js

A Javascript event emitter implementation without any dependencies. only 1.4Kb

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

event-emitter.js's Issues

Action required: Greenkeeper could not be activated 🚨

🚨 You need to enable Continuous Integration on Greenkeeper branches of this repository. 🚨

To enable Greenkeeper, you need to make sure that a commit status is reported on all branches. This is required by Greenkeeper because it uses your CI build statuses to figure out when to notify you about breaking changes.

Since we didn’t receive a CI status on the greenkeeper/initial branch, it’s possible that you don’t have CI set up yet. We recommend using Travis CI, but Greenkeeper will work with every other CI service as well.

If you have already set up a CI for this repository, you might need to check how it’s configured. Make sure it is set to run on all new branches. If you don’t want it to run on absolutely every branch, you can whitelist branches starting with greenkeeper/.

Once you have installed and configured CI on this repository correctly, you’ll need to re-trigger Greenkeeper’s initial pull request. To do this, please click the 'fix repo' button on account.greenkeeper.io.