text: 'use strict';
  
  /* Simplified implementation of DOM2 EventTarget.
   *   http://www.w3.org/TR/DOM-Level-2-Events/events.html#Events-EventTarget
   */
  
  function EventTarget() {
    this._listeners = {};
  }
  
  EventTarget.prototype.addEventListener = function(eventType, listener) {
    if (!(eventType in this._listeners)) {
      this._listeners[eventType] = [];
    }
    var arr = this._listeners[eventType];
    // #4
    if (arr.indexOf(listener) === -1) {
      // Make a copy so as not to interfere with a current dispatchEvent.
      arr = arr.concat([listener]);
    }
    this._listeners[eventType] = arr;
  };
  
  EventTarget.prototype.removeEventListener = function(eventType, listener) {
    var arr = this._listeners[eventType];
    if (!arr) {
      return;
    }
    var idx = arr.indexOf(listener);
    if (idx !== -1) {
      if (arr.length > 1) {
        // Make a copy so as not to interfere with a current dispatchEvent.
        this._listeners[eventType] = arr.slice(0, idx).concat(arr.slice(idx + 1));
      } else {
        delete this._listeners[eventType];
      }
      return;
    }
  };
  
  EventTarget.prototype.dispatchEvent = function() {
    var event = arguments[0];
    var t = event.type;
    // equivalent of Array.prototype.slice.call(arguments, 0);
    var args = arguments.length === 1 ? [event] : Array.apply(null, arguments);
    // TODO: This doesn't match the real behavior; per spec, onfoo get
    // their place in line from the /first/ time they're set from
    // non-null. Although WebKit bumps it to the end every time it's
    // set.
    if (this['on' + t]) {
      this['on' + t].apply(this, args);
    }
    if (t in this._listeners) {
      // Grab a reference to the listeners list. removeEventListener may alter the list.
      var listeners = this._listeners[t];
      for (var i = 0; i < listeners.length; i++) {
        listeners[i].apply(this, args);
      }
    }
  };
  
  module.exports = EventTarget;
  