eventjs -- JavaScript library for event dispatcher and callback list

eventjs is a JavaScript event library that provides tools that enable your application components to communicate with each other by dispatching events and listening for them. With eventjs you can easily implement signal/slot mechanism, or observer pattern.

Facts and features

• Powerful
  • Supports synchronous event dispatching and asynchronous event queue.
  • Supports event filter via mixins.
  • Configurable and extensible.
• Robust
  • Supports nested event. During the process of handling an event, a listener can safely dispatch event and append/prepend/insert/remove other listeners.
  • Doesn't depend on HTML DOM. eventjs works for non-browser environment.
  • Well tested. Backed by unit tests.
• Fast
  • Much faster than HTML DOM event listener system.
  • The EventQueue can process 5M events in 1 second (5K events per millisecond, when there are 100 event in the queue).
  • The CallbackList can invoke 1M callbacks in 1 second (1000 callbacks per millisecond).

License

Apache License, Version 2.0

Version 0.0.1

Source code

https://github.com/wqking/eventjs

Quick start

Install

Install with NPM

npm install --save wqking-eventjs

Import the module,

let eventjs = require('wqking-eventjs');

Or link to the source code directly

<script src="dist/eventjs.min.js"></script>

Name eventjs is ready to use and no need to import.

Or CDN

<script src="https://unpkg.com/wqking-eventjs/dist/eventjs.min.js"></script>

Name eventjs is ready to use and no need to import.

Using CallbackList

let callbackList = new eventjs.CallbackList();
callbackList.append(function() {
	console.log("Got callback 1.");
});
callbackList.append(() => {
	console.log("Got callback 2.");
});
callbackList.dispatch();

Using EventDispatcher

let dispatcher = new eventjs.EventDispatcher();
// Add an event 3 which is integer. The event
// can be any type such as a string.
dispatcher.appendListener(3, function() {
	console.log("Got event 3.");
});
dispatcher.appendListener(5, () => {
	console.log("Got event 5.");
});
dispatcher.appendListener(5, function() {
	console.log("Got another event 5.");
});
dispatcher.dispatch(3);
dispatcher.dispatch(5);

Using EventQueue

let queue = new eventjs.EventQueue();
queue.appendListener(3, function(s, n) {
	console.log("Got event 3, s is", s, "n is", n);
});
queue.appendListener(5, (s, n) => {
	console.log("Got event 5, s is", s, "n is", n);
});
queue.appendListener(5, function(s, n) {
	console.log("Got another event 5, s is", s, "n is", n);
});

// Enqueue the events, the first argument is always the event type.
// The listeners are not triggered during enqueue.
queue.enqueue(3, "Hello", 38);
queue.enqueue(5, "World", 58);

// Process the event queue, dispatch all queued events.
queue.process();

Documentations

• Introductions
• Tutorials of CallbackList
• Tutorials of EventDispatcher
• Tutorials of EventQueue
• Class CallbackList
• Class EventDispatcher
• Class EventQueue
• Parameters object -- configure eventjs
• Mixins -- extend eventjs
• There are source code of tutorials in the unit tests.

Run the unit tests

npm test