diff --git a/src/ol/control/rotatecontrol.js b/src/ol/control/rotatecontrol.js
index db3fc47ef5..2ccddc86cd 100644
--- a/src/ol/control/rotatecontrol.js
+++ b/src/ol/control/rotatecontrol.js
@@ -130,7 +130,7 @@ ol.control.Rotate.prototype.handlePointerUp_ = function(pointerEvent) {
 ol.control.Rotate.prototype.resetNorth_ = function() {
   var map = this.getMap();
   var view = map.getView();
-  goog.asserts.assert(goog.isDef(view));
+  goog.asserts.assert(!goog.isNull(view));
   var currentRotation = view.getRotation();
   while (currentRotation < -Math.PI) {
     currentRotation += 2 * Math.PI;
diff --git a/src/ol/interaction/doubleclickzoominteraction.js b/src/ol/interaction/doubleclickzoominteraction.js
index 8b43696863..e840045e8d 100644
--- a/src/ol/interaction/doubleclickzoominteraction.js
+++ b/src/ol/interaction/doubleclickzoominteraction.js
@@ -50,7 +50,7 @@ ol.interaction.DoubleClickZoom.prototype.handleMapBrowserEvent =
     var anchor = mapBrowserEvent.coordinate;
     var delta = browserEvent.shiftKey ? -this.delta_ : this.delta_;
     var view = map.getView();
-    goog.asserts.assert(goog.isDef(view));
+    goog.asserts.assert(!goog.isNull(view));
     ol.interaction.Interaction.zoomByDelta(
         map, view, delta, anchor, this.duration_);
     mapBrowserEvent.preventDefault();
diff --git a/src/ol/interaction/draganddropinteraction.js b/src/ol/interaction/draganddropinteraction.js
index 0e4f590ad3..7ad970635d 100644
--- a/src/ol/interaction/draganddropinteraction.js
+++ b/src/ol/interaction/draganddropinteraction.js
@@ -100,7 +100,7 @@ ol.interaction.DragAndDrop.prototype.handleResult_ = function(file, result) {
   var projection = this.reprojectTo_;
   if (goog.isNull(projection)) {
     var view = map.getView();
-    goog.asserts.assert(goog.isDef(view));
+    goog.asserts.assert(!goog.isNull(view));
     projection = view.getProjection();
     goog.asserts.assert(goog.isDef(projection));
   }
diff --git a/src/ol/interaction/dragzoominteraction.js b/src/ol/interaction/dragzoominteraction.js
index 6074caba7b..db190f2111 100644
--- a/src/ol/interaction/dragzoominteraction.js
+++ b/src/ol/interaction/dragzoominteraction.js
@@ -54,7 +54,7 @@ goog.inherits(ol.interaction.DragZoom, ol.interaction.DragBox);
 ol.interaction.DragZoom.prototype.onBoxEnd = function() {
   var map = this.getMap();
   var view = map.getView();
-  goog.asserts.assert(goog.isDef(view));
+  goog.asserts.assert(!goog.isNull(view));
   var extent = this.getGeometry().getExtent();
   var center = ol.extent.getCenter(extent);
   var size = map.getSize();
diff --git a/src/ol/interaction/keyboardpaninteraction.js b/src/ol/interaction/keyboardpaninteraction.js
index c49aa6f1e3..62dab76038 100644
--- a/src/ol/interaction/keyboardpaninteraction.js
+++ b/src/ol/interaction/keyboardpaninteraction.js
@@ -70,7 +70,7 @@ ol.interaction.KeyboardPan.prototype.handleMapBrowserEvent =
         keyCode == goog.events.KeyCodes.UP)) {
       var map = mapBrowserEvent.map;
       var view = map.getView();
-      goog.asserts.assert(goog.isDef(view));
+      goog.asserts.assert(!goog.isNull(view));
       var viewState = view.getState();
       var mapUnitsDelta = viewState.resolution * this.pixelDelta_;
       var deltaX = 0, deltaY = 0;
diff --git a/src/ol/interaction/keyboardzoominteraction.js b/src/ol/interaction/keyboardzoominteraction.js
index 830aa4de60..a629ae8ff8 100644
--- a/src/ol/interaction/keyboardzoominteraction.js
+++ b/src/ol/interaction/keyboardzoominteraction.js
@@ -70,7 +70,7 @@ ol.interaction.KeyboardZoom.prototype.handleMapBrowserEvent =
       var delta = (charCode == '+'.charCodeAt(0)) ? this.delta_ : -this.delta_;
       map.render();
       var view = map.getView();
-      goog.asserts.assert(goog.isDef(view));
+      goog.asserts.assert(!goog.isNull(view));
       ol.interaction.Interaction.zoomByDelta(
           map, view, delta, undefined, this.duration_);
       mapBrowserEvent.preventDefault();
diff --git a/src/ol/interaction/mousewheelzoominteraction.js b/src/ol/interaction/mousewheelzoominteraction.js
index 9702bb3701..0e0f713d18 100644
--- a/src/ol/interaction/mousewheelzoominteraction.js
+++ b/src/ol/interaction/mousewheelzoominteraction.js
@@ -101,7 +101,7 @@ ol.interaction.MouseWheelZoom.prototype.doZoom_ = function(map) {
   var delta = goog.math.clamp(this.delta_, -maxDelta, maxDelta);
 
   var view = map.getView();
-  goog.asserts.assert(goog.isDef(view));
+  goog.asserts.assert(!goog.isNull(view));
 
   map.render();
   ol.interaction.Interaction.zoomByDelta(map, view, -delta, this.lastAnchor_,
diff --git a/src/ol/map.js b/src/ol/map.js
index b013cd4cdd..792f24041b 100644
--- a/src/ol/map.js
+++ b/src/ol/map.js
@@ -753,7 +753,7 @@ goog.exportProperty(
 /**
  * Get the view associated with this map. A view manages properties such as
  * center and resolution.
- * @return {ol.View|undefined} The view that controls this map.
+ * @return {ol.View} The view that controls this map.
  * @observable
  * @api stable
  */
@@ -988,7 +988,7 @@ ol.Map.prototype.handleViewChanged_ = function() {
     this.viewPropertyListenerKey_ = null;
   }
   var view = this.getView();
-  if (goog.isDefAndNotNull(view)) {
+  if (!goog.isNull(view)) {
     this.viewPropertyListenerKey_ = goog.events.listen(
         view, ol.ObjectEventType.PROPERTYCHANGE,
         this.handleViewPropertyChanged_, false, this);
@@ -1061,7 +1061,7 @@ ol.Map.prototype.isDef = function() {
     return false;
   }
   var view = this.getView();
-  if (!goog.isDef(view) || !view.isDef()) {
+  if (goog.isNull(view) || !view.isDef()) {
     return false;
   }
   return true;
@@ -1189,7 +1189,7 @@ ol.Map.prototype.renderFrame_ = function(time) {
   /** @type {?olx.FrameState} */
   var frameState = null;
   if (goog.isDef(size) && hasArea(size) &&
-      goog.isDef(view) && view.isDef()) {
+      !goog.isNull(view) && view.isDef()) {
     var viewHints = view.getHints();
     var layerStatesArray = this.getLayerGroup().getLayerStatesArray();
     var layerStates = {};