fixing inheritance bug in event emitter

lib/pilot/event_emitter.js

@@ -43,27 +43,34 @@ var EventEmitter = {};
 
 EventEmitter._emit =
 EventEmitter._dispatchEvent = function(eventName, e) {
-    this._eventRegistry = this._eventRegistry || {};
+    if (!this.hasOwnProperty('_eventRegistry')) {
+        return;
+    }
 
     var listeners = this._eventRegistry[eventName];
-    if (!listeners || !listeners.length) return;
+    if (!listeners || !listeners.length) {
+        return;
+    }
 
     var e = e || {};
     e.type = eventName;
 
-    for (var i=0; i<listeners.length; i++) {
+    for (var i = 0; i < listeners.length; i++) {
         listeners[i](e);
     }
 };
 
 EventEmitter.on =
 EventEmitter.addEventListener = function(eventName, callback) {
-    this._eventRegistry = this._eventRegistry || {};
+    if (!this.hasOwnProperty('_eventRegistry')) {
+        this._eventRegistry = {};
+    }
 
     var listeners = this._eventRegistry[eventName];
     if (!listeners) {
-      var listeners = this._eventRegistry[eventName] = [];
+        var listeners = this._eventRegistry[eventName] = [];
     }
+
     if (listeners.indexOf(callback) == -1) {
         listeners.push(callback);
     }
@@ -71,12 +78,15 @@ EventEmitter.addEventListener = function(eventName, callback) {
 
 EventEmitter.removeListener =
 EventEmitter.removeEventListener = function(eventName, callback) {
-    this._eventRegistry = this._eventRegistry || {};
+    if (!this.hasOwnProperty('_eventRegistry')) {
+        return;
+    }
 
     var listeners = this._eventRegistry[eventName];
     if (!listeners) {
-      return;
+        return;
     }
+
     var index = listeners.indexOf(callback);
     if (index !== -1) {
         listeners.splice(index, 1);
@@ -84,7 +94,9 @@ EventEmitter.removeEventListener = function(eventName, callback) {
 };
 
 EventEmitter.removeAllListeners = function(eventName) {
-    if (this._eventRegistry) this._eventRegistry[eventName] = [];
+    if (this.hasOwnProperty('_eventRegistry')) {
+        this._eventRegistry[eventName] = [];
+    }
 };
 
 exports.EventEmitter = EventEmitter;