Sister

Foundation for your emitter implementation.

I have observed that there is a tendency to write your own implementation of event emitter. I have written a starter pack for those wishing to improve upon existing variations of event emitter implementation.

Please submit your implementation to the index when you are done.

In All Seriousness

Sister is 0.5kb event emitter that does three things: on, off and trigger. It performs well (~18,313,548 operations/sec in browser). If you need something more advanced, consider one of the existing, mature alternatives.

Node

Download using NPM:

npm install sister --save

Browser

Download using Bower:

bower install sister --save

In browser, use gajus.Sister window object.

Methods

• emitter.on(event, handler)
• emitter.off(listener)
• emitter.trigger(event, data)

Parameters

• emitter Instance of the Sister() object.
• event Name of the event.
• handler A function to execute when the event is triggered.
• listener Event listener.

emitter.on(event, handler)

• Add handler for event.
• Return listener.

emitter.off(listener)

• Remove listener.

emitter.trigger(event, data)

• Invoke event listeners (in sequence) with the supplied argument.
• Return emitter.

Usage

var Sister = require('sister'),
    emitter = Sister(),
    listener;

listener = emitter.on('foo', console.log);
emitter.trigger('foo', 'bar');
emitter.off(listener);
emitter.trigger('foo', 'baz');

This example will print "bar" in the console.log.

Similar Libraries

There are several existing alternatives that you might want to consider before starting to write your own implementation of an event emitter.