Simple Events as a functional mixin

has_events.js

var hasEvents = (function() {
  function on(name, callback, listener) {
    var listener = listener || this
    this._events = this._events || []

    this._events.push({
      name: name,
      callback: callback,
      listener: listener
    })
  }

  function off(name, listener) {
    var listener = listener || this
    this._events = this._events || []

    this._events = this._events.filter(function(event) {
      console.log([event.listener === listener, event.name === name])
      return event.listener !== listener || event.name !== name
    })
  }

  function listenTo(target, name, callback) {
    var self = this

    target.on(name, function() {
      callback.apply(self, arguments)
    }, this)
  }

  function stopListening(target, name) {
    target.off(name, this)
  }

  function trigger(name) {
    var self = this
    var args = Array.prototype.slice.call(arguments, 1)

    this._events = this._events || []

    this._events.forEach(function(event) {
      if (event.name === name) {
        setTimeout(function() {
          event.callback.apply(self, args)
        }, 0)
      }
    })
  }

  return function() {
    this.on            = on
    this.off           = off
    this.listenTo      = listenTo
    this.stopListening = stopListening
    this.trigger       = trigger
  }
})()