Adding changes from feedback:

- Cleared listners on emit
- Added an off method to Events
- Added destory to State

src/kibana/components/state_management/app_state_factory.js

@@ -25,7 +25,7 @@ define(function (require) {
         // Check to see if the state already exists. If it does then we need
         // to call the destory method.
         if (!_.isUndefined(currentAppState)) {
-          currentAppState.$destroy();
+          currentAppState.destroy();
         }
         currentAppState = new AppState(defaults);
 

src/kibana/components/state_management/state.js

@@ -5,8 +5,7 @@ define(function (require) {
   var applyDiff = require('utils/diff_object');
 
   return function StateProvider(Private, $rootScope, $location) {
-    var BaseObject = Private(require('components/state_management/_base_object'));
-    var Events = Private(require('components/state_management/_events'));
+    var Events = Private(require('factories/_events'));
 
     _.inherits(State, Events);
     function State(urlParam, defaults) {
@@ -76,6 +75,14 @@ define(function (require) {
       this.on('fetch_with_changes', cb);
     };
 
+    /**
+     * Cleans up the state object
+     * @returns {void}
+     */
+    State.prototype.destroy = function () {
+      this.off(); // removes all listners
+    };
+
     return State;
 
   };

src/kibana/factories/_events.js

@@ -2,7 +2,7 @@ define(function (require) {
   var _ = require('lodash');
 
   return function EventsProvider(Private, PromiseEmitter) {
-    var BaseObject = Private(require('components/state_management/_base_object'));
+    var BaseObject = Private(require('factories/_base_object'));
 
     _.inherits(Events, BaseObject);
     function Events() {
@@ -24,10 +24,35 @@ define(function (require) {
       }
 
       return new PromiseEmitter(function (resolve, reject, defer) {
+        defer._handler = handler;
         self._listeners[name].push(defer);
       }, handler);
     };
 
+    /**
+     * Removes a event listner
+     * @param {string} name The name of the event
+     * @param {function} [handler] The handler to remove
+     * @return {void}
+     */
+    Events.prototype.off = function (name, handler) {
+      if (_.isEmpty(name) && _.isEmpty(handler)) {
+        this._listeners = {};
+      }
+
+      // exit early if there is not an event that matches
+      if (!this._listeners[name]) return;
+
+      // If no hander remove all the events
+      if (_.isEmpty(handler)) {
+        delete this._listeners[name];
+      } else {
+        this._listeners[name] = _.filter(this._listeners[name], function (defer) {
+          return handler !== defer._handler;
+        });
+      }
+    };
+
     /**
      * Emits and event using the PromiseEmitter
      * @param {string} name The name of the event
@@ -38,7 +63,9 @@ define(function (require) {
       var args = Array.prototype.slice.call(arguments);
       var name = args.shift();
       if (this._listeners[name]) {
-        _.each(this._listeners[name], function (defer) {
+        // We need to empty the array when we resolve the listners. PromiseEmitter
+        // will regenerate the listners array with new promises.
+        _.each(this._listeners[name].slice(0), function (defer) {
           defer.resolve.apply(defer, args);
         });
       }

test/unit/index.html

@@ -74,10 +74,10 @@
           'specs/utils/versionmath',
           'specs/utils/routes/index',
           'specs/courier/search_source/_get_normalized_sort',
-          'specs/state_management/_base_object',
+          'specs/factories/_base_object',
           'specs/state_management/state',
           'specs/utils/diff_object',
-          'specs/state_management/_events'
+          'specs/factories/_events'
         ], function (kibana, sinon) {
           kibana.load(function () {
             var xhr = sinon.useFakeXMLHttpRequest();

test/unit/specs/factories/_base_object.js

@@ -17,7 +17,7 @@ define(function (require) {
 
         inject(function (_$rootScope_, Private) {
           $rootScope = _$rootScope_;
-          BaseObject = Private(require('components/state_management/_base_object'));
+          BaseObject = Private(require('factories/_base_object'));
         });
       });
 

test/unit/specs/factories/_events.js

@@ -0,0 +1,86 @@
+define(function (require) {
+  var angular = require('angular');
+  var _ = require('lodash');
+  var sinon = require('sinon/sinon');
+  require('services/private');
+
+  // Load kibana
+  require('index');
+
+  describe('State Management', function () {
+    describe('Events', function () {
+      var $rootScope;
+      var Events;
+
+      beforeEach(function () {
+        module('kibana');
+
+        inject(function (_$rootScope_, Private) {
+          $rootScope = _$rootScope_;
+          Events = Private(require('factories/_events'));
+        });
+      });
+
+      it('should handle on events', function (done) {
+        var obj = new Events();
+        obj.on('test', function (message) {
+          expect(message).to.equal('Hello World');
+          done();
+        });
+        obj.emit('test', 'Hello World');
+        $rootScope.$apply();
+      });
+
+      it('should work with inherited objects', function (done) {
+        _.inherits(MyEventedObject, Events);
+        function MyEventedObject() {
+          MyEventedObject.Super.call(this);
+        }
+        var obj = new MyEventedObject();
+        obj.on('test', function (message) {
+          expect(message).to.equal('Hello World');
+          done();
+        });
+        obj.emit('test', 'Hello World');
+        $rootScope.$apply();
+      });
+
+      it('should clear events when off is called', function () {
+        var obj = new Events();
+        obj.on('test', _.noop);
+        expect(obj._listeners).to.have.property('test');
+        expect(obj._listeners['test']).to.have.length(1);
+        obj.off();
+        expect(obj._listeners).to.not.have.property('test');
+      });
+
+      it('should clear a specific handler when off is called for an event', function () {
+        var obj = new Events();
+        var handler1 = sinon.stub();
+        var handler2 = sinon.stub();
+        obj.on('test', handler1);
+        obj.on('test', handler2);
+        expect(obj._listeners).to.have.property('test');
+        obj.off('test', handler1);
+        obj.emit('test', 'Hello World');
+        $rootScope.$apply();
+        sinon.assert.calledOnce(handler2);
+        sinon.assert.notCalled(handler1);
+      });
+
+      it('should clear a all handlers when off is called for an event', function () {
+        var obj = new Events();
+        var handler1 = sinon.stub();
+        obj.on('test', handler1);
+        expect(obj._listeners).to.have.property('test');
+        obj.off('test');
+        expect(obj._listeners).to.not.have.property('test');
+        obj.emit('test', 'Hello World');
+        $rootScope.$apply();
+        sinon.assert.notCalled(handler1);
+      });
+
+    });
+  });
+
+});

test/unit/specs/state_management/_events.js

@@ -1,51 +0,0 @@
-define(function (require) {
-  var angular = require('angular');
-  var _ = require('lodash');
-  var sinon = require('sinon/sinon');
-  require('services/private');
-
-  // Load kibana
-  require('index');
-
-  describe('State Management', function () {
-    describe('Events', function () {
-      var $rootScope;
-      var Events;
-
-      beforeEach(function () {
-        module('kibana');
-
-        inject(function (_$rootScope_, Private) {
-          $rootScope = _$rootScope_;
-          Events = Private(require('components/state_management/_events'));
-        });
-      });
-
-      it('should handle on events', function (done) {
-        var obj = new Events();
-        obj.on('test', function (message) {
-          expect(message).to.equal('Hello World');
-          done();
-        });
-        obj.emit('test', 'Hello World');
-        $rootScope.$apply();
-      });
-
-      it('should work with inherited objects', function (done) {
-        _.inherits(MyEventedObject, Events);
-        function MyEventedObject() {
-          MyEventedObject.Super.call(this);
-        }
-        var obj = new MyEventedObject();
-        obj.on('test', function (message) {
-          expect(message).to.equal('Hello World');
-          done();
-        });
-        obj.emit('test', 'Hello World');
-        $rootScope.$apply();
-      });
-
-    });
-  });
-
-});

test/unit/specs/state_management/state.js

@@ -19,7 +19,7 @@ define(function (require) {
           $location = _$location_;
           $rootScope = _$rootScope_;
           State = Private(require('components/state_management/state'));
-          Events = Private(require('components/state_management/_events'));
+          Events = Private(require('factories/_events'));
         });
       });
 
@@ -48,12 +48,6 @@ define(function (require) {
         $rootScope.$apply();
       });
 
-      it('should fetch the state from $location.search()', function () {
-        var state = new State();
-        $location.search({ _s: '(foo:bar)' });
-        state.fetch();
-        expect(state).to.have.property('foo', 'bar');
-      });
 
       it('should emit an event if changes are fetched', function (done) {
         var state = new State();