Emmy

High-level event functions for green components.

It uses target events, if possible, and then falls back to own safe implementation.

It handles multiple events on(el, 'click touchstart', cb) and namespaces on(el, 'click.x', cb); off(el, 'click.x');.

It is best as an universal way to bind events to anything: plain objects, elements, jQuery objects, Backbone models, color, webWorkers etc.

Use

$ npm install emmy

var on = require('emmy/on');
var once = require('emmy/once');
var off = require('emmy/off');
var emit = require('emmy/emit');

on(target, 'evt', function(){});
emit(target, 'evt', data1, data2);
off(target, 'evt');

//typical use-case
once(webWorker, 'message', function(){...});

API

on(target, event, callback)

Bind an event handler to a target.

once(target, event, callback)

Bind single-shot event handler to a target.

off(target, event?, callback?)

Unbind event handler from a target. If calback isn’t passed - unbind all callbacks for an event. If no event passed - unbind all known callbacks for any events.

emit(target, event, callback, data1, data2, ...)

Emit an event on a target, passing dataN. If target is an element then data1 is e.details, data2 is bubbles. So to fire bubbling event, call emit(element, 'click', null, true).

later(target, event, callback, delay)

Bind an event handler which triggers a delay later than actual event occures.

throttle(target, event, callback, interval)

Bind an event handler which won’t be called more often than an interval.

delegate(target, event, callback, selector)

Bind an event handler catching bubbling events from target’s descendants.

not(target, event, callback, selector)

Bind an event handler catching events from target’s descendants ignoring ones that match selector.

keypass(target, event, callback, keylist)

Bind an event handler which triggers only if e.which or e.keyCode is one from the defined keylist. Any keyname can be declared instead of a code.

listeners(target, event?)

Get list of listeners registered for an event.

Afterword

Emmy implements maximally minimal coverage for main use-cases. It’s not supposed to recognize broad range of input values. For that take a look at enot (event notation system) — an easy wrapper for emmy with humanized event notation.

There’s also a similar project - emmitt, but it can’t emit bubbling events nor DOM-events, it does not provide an Emitter class and a bunch of useful methods.