@smoovy/emitter
v1.1.0
Published
Simple event emitter
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@smoovy/emitter
Installation
yarn add @smoovy/emitter
or
npm install --save @smoovy/emitter
The event emitter
Import the emitter as usual:
import { EventEmitter } from '@smoovy/emitter';
Usage
To use the event emitter you can either create a new instance directly or use it as a parent class.
const emitter = new EventEmitter();
// or
class UltraFancyEmitter extends EventEmitter {}
Emitting events
You have multiple options when it comes to the emission of events:
// Emit a single value
emitter.emit('eventName', 'A random string');
// Emit an other data type (object)
emitter.emit('eventName', { name: 'Mistadobalina' });
// Emit multiple events with different data types
emitter.emit({
eventName1: 'Some data',
eventName2: [ 1, 2, 3, 4 ]
});
Listening/Unlistening for events
Listening to events is pretty simple:
emitter.on('eventName', (data) => {
// Handle your data
});
To unlisten you have two options:
const listener = (data) => {};
const unlisten = emitter.on('eventName', listener);
// Unlisten from callback or...
unlisten();
// Unlisten the old-fashioned way
emitter.off('eventName', listener);
When you have many listeners going wild in your application, you can use this litte helper function to stack those:
import { listenCompose } from '@smoovy/listener';
const unlisten = listenCompose(
emitter.on('eventName1', () => {}),
emitter.on('eventName2', () => {}),
emitter.on('eventName3', () => {})
);
// Easily unsubcribe from all simultaneously
unlisten();
listenCompose
simply merges all "unsubscribe callbacks" into one
Reflecting events
Reflect events to a different emitter. Muted events will not be reflects:
const reflectedEmitter = new Emitter();
// Reflect events to reflectedEmitter
emitter.reflectEvents(reflectedEmitter);
// Listen for events
reflectedEmitter.on('eventName1', (msg) => console.log(msg));
// Dispatch event in base emitter
emitter.emit('eventName1', 'reflected'); // Displays 'reflected'
// Remove reflected emitters
emitter.unreflectEvents();
License
See the LICENSE file for license rights and limitations (MIT).