The basicest eventdispatcher

eventdispatcher.js

function EventDispatcher() {
  this._listeners = {};
}
EventDispatcher.prototype.on = function(event, callback) {
  if (!this._listeners[event]) this._listeners[event] = [];
  this._listeners[event].push(callback);
}
EventDispatcher.prototype.trigger = function(event, data) {
  if (!this._listeners[event]) return;
  for (var i = 0; i < this._listeners[event].length; i++) {
    this._listeners[event][i](data);
  }
}
EventDispatcher.prototype.off = function(event, callback) {
  if (!_this.listeners[event]) return;
  var index = _this.listeners[event].indexOf(callback);
  if (index > -1) _this.listeners[event] = _this.listeners[event].splice(index, 1);
}

inheritance.js

function SomeClass() {
  EventDispatcher.call(this);
  
  // Do stuff
}
SomeClass.prototype = Object.create(EventDispatcher.prototype);
SomeClass.prototype.constructor = SomeClass;