A custom event emitter for Node.js and the browser.
Its aim is to provide its user with a lot of event emitting sugar while remaining lightweight and fast.
You can install Emmett through npm:
npm install --save emmettvar Emitter = require('emmett');
var emitter = new Emitter();Node.js
var util = require('util'),
Emitter = require('emmett');
function MyObject() {
Emitter.call(this);
}
util.inherits(MyObject, Emitter);ES6 class
import Emitter from 'emmett';
class MyObject extends Emitter {
/* ... */
}// Basic
emitter.on('eventName', callback);
// Once
emitter.once('eventName', callback);
// Using ES6 symbol as event name
const sym = Symbol();
emitter.on(sym, callback);
// Matching event names with a regex
emitter.on(/^event/, callback);
// Options
emitter.on('eventName', callback, {scope: customScope, once: true});
// Polymorphisms
emitter.on(['event1', 'event2'], callback);
emitter.on({
event1: callback1,
event2: callback2
});
// Listening to every events
emitter.on(callback);Events are objects having the following keys:
- data: the data attached to the event.
- type: the event type.
- target: the event emitter.
emitter.on('myEvent', function(e) {
console.log(e.data);
});
emitter.emit('myEvent', 'Hello World!');
// Will print "Hello World!" in the console// Basic
emitter.off('eventName', callback);
// Removing every listeners attached to the given event
emitter.off('eventName');
// Removing the callback from any event
emitter.off(callback);
// Polymorphisms
emitter.off(['event1', 'event2'], callback);
emitter.off({
event1: callback1,
event2: callback2
});
// Removing every listeners
emitter.unbindAll();// Basic
emitter.emit('eventName');
// With data
emitter.emit('eventName', {hello: 'world'});
// Polymorphisms
emitter.emit(['event1', 'event2']);
emitter.emit(['event1', 'event2'], {hello: 'world'});
emitter.emit({
event1: 'hey',
event2: 'ho'
});// Return every matching handlers for a given event name
emitter.listeners('eventName');While disabled, emitting events won't produce nothing.
emitter.disable();
emitter.enable();Killing an emitter will remove all its listeners and make it inoperant in the future.
emitter.kill();Do not hesitate to contribute to the library. Be sure to add and pass any relevant unit test before submitting any code.
# Installing the dev version
git clone http://github.com/jacomyal/emmett
cd emmett
# Installing dependencies
npm install
# Running unit tests
npm test
# Lint the code
npm run lint