diff --git a/src/ol/interaction/doubleclickzoominteraction.js b/src/ol/interaction/doubleclickzoominteraction.js
index a874369363..404e2a1310 100644
--- a/src/ol/interaction/doubleclickzoominteraction.js
+++ b/src/ol/interaction/doubleclickzoominteraction.js
@@ -56,7 +56,7 @@ ol.interaction.DoubleClickZoom.handleEvent = function(mapBrowserEvent) {
     var anchor = mapBrowserEvent.coordinate;
     var delta = browserEvent.shiftKey ? -this.delta_ : this.delta_;
     var view = map.getView();
-    goog.asserts.assert(!goog.isNull(view), 'view should not be null');
+    goog.asserts.assert(view, 'map must have a 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 3c8fdfb9f4..105461a143 100644
--- a/src/ol/interaction/draganddropinteraction.js
+++ b/src/ol/interaction/draganddropinteraction.js
@@ -98,11 +98,11 @@ ol.interaction.DragAndDrop.prototype.handleDrop_ = function(event) {
  */
 ol.interaction.DragAndDrop.prototype.handleResult_ = function(file, result) {
   var map = this.getMap();
-  goog.asserts.assert(!goog.isNull(map), 'map should not be null');
+  goog.asserts.assert(map, 'map must be set');
   var projection = this.projection_;
-  if (goog.isNull(projection)) {
+  if (!projection) {
     var view = map.getView();
-    goog.asserts.assert(!goog.isNull(view), 'view should not be null');
+    goog.asserts.assert(view, 'map must have view');
     projection = view.getProjection();
     goog.asserts.assert(projection !== undefined,
         'projection should be defined');
@@ -114,7 +114,7 @@ ol.interaction.DragAndDrop.prototype.handleResult_ = function(file, result) {
     var formatConstructor = formatConstructors[i];
     var format = new formatConstructor();
     var readFeatures = this.tryReadFeatures_(format, result);
-    if (!goog.isNull(readFeatures)) {
+    if (readFeatures) {
       var featureProjection = format.readProjection(result);
       var transform = ol.proj.getTransform(featureProjection, projection);
       var j, jj;
@@ -154,14 +154,14 @@ ol.interaction.DragAndDrop.prototype.setMap = function(map) {
     goog.events.unlistenByKey(this.dropListenKey_);
     this.dropListenKey_ = undefined;
   }
-  if (!goog.isNull(this.fileDropHandler_)) {
+  if (this.fileDropHandler_) {
     goog.dispose(this.fileDropHandler_);
     this.fileDropHandler_ = null;
   }
   goog.asserts.assert(this.dropListenKey_ === undefined,
       'this.dropListenKey_ should be undefined');
   goog.base(this, 'setMap', map);
-  if (!goog.isNull(map)) {
+  if (map) {
     this.fileDropHandler_ = new goog.events.FileDropHandler(map.getViewport());
     this.dropListenKey_ = goog.events.listen(
         this.fileDropHandler_, goog.events.FileDropHandler.EventType.DROP,
diff --git a/src/ol/interaction/dragpaninteraction.js b/src/ol/interaction/dragpaninteraction.js
index ae78fc37ad..1230e91a39 100644
--- a/src/ol/interaction/dragpaninteraction.js
+++ b/src/ol/interaction/dragpaninteraction.js
@@ -77,7 +77,7 @@ ol.interaction.DragPan.handleDragEvent_ = function(mapBrowserEvent) {
   if (this.kinetic_) {
     this.kinetic_.update(centroid[0], centroid[1]);
   }
-  if (!goog.isNull(this.lastCentroid)) {
+  if (this.lastCentroid) {
     var deltaX = this.lastCentroid[0] - centroid[0];
     var deltaY = centroid[1] - this.lastCentroid[1];
     var map = mapBrowserEvent.map;
@@ -145,7 +145,7 @@ ol.interaction.DragPan.handleDownEvent_ = function(mapBrowserEvent) {
       view.setHint(ol.ViewHint.INTERACTING, 1);
     }
     map.render();
-    if (!goog.isNull(this.kineticPreRenderFn_) &&
+    if (this.kineticPreRenderFn_ &&
         map.removePreRenderFunction(this.kineticPreRenderFn_)) {
       view.setCenter(mapBrowserEvent.frameState.viewState.center);
       this.kineticPreRenderFn_ = null;
diff --git a/src/ol/interaction/dragzoominteraction.js b/src/ol/interaction/dragzoominteraction.js
index 82eefa25ff..a5e7a2f75e 100644
--- a/src/ol/interaction/dragzoominteraction.js
+++ b/src/ol/interaction/dragzoominteraction.js
@@ -61,7 +61,7 @@ ol.interaction.DragZoom.prototype.onBoxEnd = function() {
   var map = this.getMap();
 
   var view = map.getView();
-  goog.asserts.assert(!goog.isNull(view), 'view should not be null');
+  goog.asserts.assert(view, 'map must have view');
 
   var size = map.getSize();
   goog.asserts.assert(size !== undefined, 'size should be defined');
diff --git a/src/ol/interaction/drawinteraction.js b/src/ol/interaction/drawinteraction.js
index a0f1ff7c4c..aa8ae8b56f 100644
--- a/src/ol/interaction/drawinteraction.js
+++ b/src/ol/interaction/drawinteraction.js
@@ -367,7 +367,7 @@ ol.interaction.Draw.handleDownEvent_ = function(event) {
       this.freehandCondition_(event)) {
     this.downPx_ = event.pixel;
     this.freehand_ = true;
-    if (goog.isNull(this.finishCoordinate_)) {
+    if (!this.finishCoordinate_) {
       this.startDrawing_(event);
     }
     return true;
@@ -393,7 +393,7 @@ ol.interaction.Draw.handleUpEvent_ = function(event) {
   var pass = true;
   if (squaredDistance <= this.squaredClickTolerance_) {
     this.handlePointerMove_(event);
-    if (goog.isNull(this.finishCoordinate_)) {
+    if (!this.finishCoordinate_) {
       this.startDrawing_(event);
       if (this.mode_ === ol.interaction.DrawMode.POINT) {
         this.finishDrawing();
@@ -418,7 +418,7 @@ ol.interaction.Draw.handleUpEvent_ = function(event) {
  * @private
  */
 ol.interaction.Draw.prototype.handlePointerMove_ = function(event) {
-  if (!goog.isNull(this.finishCoordinate_)) {
+  if (this.finishCoordinate_) {
     this.modifyDrawing_(event);
   } else {
     this.createOrUpdateSketchPoint_(event);
@@ -435,7 +435,7 @@ ol.interaction.Draw.prototype.handlePointerMove_ = function(event) {
  */
 ol.interaction.Draw.prototype.atFinish_ = function(event) {
   var at = false;
-  if (!goog.isNull(this.sketchFeature_)) {
+  if (this.sketchFeature_) {
     var potentiallyDone = false;
     var potentiallyFinishCoordinates = [this.finishCoordinate_];
     if (this.mode_ === ol.interaction.DrawMode.LINE_STRING) {
@@ -474,7 +474,7 @@ ol.interaction.Draw.prototype.atFinish_ = function(event) {
  */
 ol.interaction.Draw.prototype.createOrUpdateSketchPoint_ = function(event) {
   var coordinates = event.coordinate.slice();
-  if (goog.isNull(this.sketchPoint_)) {
+  if (!this.sketchPoint_) {
     this.sketchPoint_ = new ol.Feature(new ol.geom.Point(coordinates));
     this.updateSketchFeatures_();
   } else {
@@ -505,7 +505,7 @@ ol.interaction.Draw.prototype.startDrawing_ = function(event) {
       this.sketchLineCoords_ = this.sketchCoords_;
     }
   }
-  if (!goog.isNull(this.sketchLineCoords_)) {
+  if (this.sketchLineCoords_) {
     this.sketchLine_ = new ol.Feature(
         new ol.geom.LineString(this.sketchLineCoords_));
   }
@@ -548,10 +548,9 @@ ol.interaction.Draw.prototype.modifyDrawing_ = function(event) {
   }
   last[0] = coordinate[0];
   last[1] = coordinate[1];
-  goog.asserts.assert(!goog.isNull(this.sketchCoords_),
-      'sketchCoords_ must not be null');
+  goog.asserts.assert(this.sketchCoords_, 'sketchCoords_ expected');
   this.geometryFunction_(this.sketchCoords_, geometry);
-  if (!goog.isNull(this.sketchPoint_)) {
+  if (this.sketchPoint_) {
     var sketchPointGeom = this.sketchPoint_.getGeometry();
     goog.asserts.assertInstanceof(sketchPointGeom, ol.geom.Point,
         'sketchPointGeom should be an ol.geom.Point');
@@ -560,7 +559,7 @@ ol.interaction.Draw.prototype.modifyDrawing_ = function(event) {
   var sketchLineGeom;
   if (geometry instanceof ol.geom.Polygon &&
       this.mode_ !== ol.interaction.DrawMode.POLYGON) {
-    if (goog.isNull(this.sketchLine_)) {
+    if (!this.sketchLine_) {
       this.sketchLine_ = new ol.Feature(new ol.geom.LineString(null));
     }
     var ring = geometry.getLinearRing(0);
@@ -569,7 +568,7 @@ ol.interaction.Draw.prototype.modifyDrawing_ = function(event) {
         'sketchLineGeom must be an ol.geom.LineString');
     sketchLineGeom.setFlatCoordinates(
         ring.getLayout(), ring.getFlatCoordinates());
-  } else if (!goog.isNull(this.sketchLineCoords_)) {
+  } else if (this.sketchLineCoords_) {
     sketchLineGeom = this.sketchLine_.getGeometry();
     goog.asserts.assertInstanceof(sketchLineGeom, ol.geom.LineString,
         'sketchLineGeom must be an ol.geom.LineString');
@@ -652,8 +651,7 @@ ol.interaction.Draw.prototype.removeLastPoint = function() {
  */
 ol.interaction.Draw.prototype.finishDrawing = function() {
   var sketchFeature = this.abortDrawing_();
-  goog.asserts.assert(!goog.isNull(sketchFeature),
-      'sketchFeature should not be null');
+  goog.asserts.assert(sketchFeature, 'sketchFeature expected to be truthy');
   var coordinates = this.sketchCoords_;
   var geometry = sketchFeature.getGeometry();
   goog.asserts.assertInstanceof(geometry, ol.geom.SimpleGeometry,
@@ -685,10 +683,10 @@ ol.interaction.Draw.prototype.finishDrawing = function() {
       ol.interaction.DrawEventType.DRAWEND, sketchFeature));
 
   // Then insert feature
-  if (!goog.isNull(this.features_)) {
+  if (this.features_) {
     this.features_.push(sketchFeature);
   }
-  if (!goog.isNull(this.source_)) {
+  if (this.source_) {
     this.source_.addFeature(sketchFeature);
   }
 };
@@ -702,7 +700,7 @@ ol.interaction.Draw.prototype.finishDrawing = function() {
 ol.interaction.Draw.prototype.abortDrawing_ = function() {
   this.finishCoordinate_ = null;
   var sketchFeature = this.sketchFeature_;
-  if (!goog.isNull(sketchFeature)) {
+  if (sketchFeature) {
     this.sketchFeature_ = null;
     this.sketchPoint_ = null;
     this.sketchLine_ = null;
@@ -750,13 +748,13 @@ ol.interaction.Draw.prototype.shouldStopEvent = goog.functions.FALSE;
  */
 ol.interaction.Draw.prototype.updateSketchFeatures_ = function() {
   var sketchFeatures = [];
-  if (!goog.isNull(this.sketchFeature_)) {
+  if (this.sketchFeature_) {
     sketchFeatures.push(this.sketchFeature_);
   }
-  if (!goog.isNull(this.sketchLine_)) {
+  if (this.sketchLine_) {
     sketchFeatures.push(this.sketchLine_);
   }
-  if (!goog.isNull(this.sketchPoint_)) {
+  if (this.sketchPoint_) {
     sketchFeatures.push(this.sketchPoint_);
   }
   var overlaySource = this.overlay_.getSource();
@@ -771,7 +769,7 @@ ol.interaction.Draw.prototype.updateSketchFeatures_ = function() {
 ol.interaction.Draw.prototype.updateState_ = function() {
   var map = this.getMap();
   var active = this.getActive();
-  if (goog.isNull(map) || !active) {
+  if (!map || !active) {
     this.abortDrawing_();
   }
   this.overlay_.setMap(active ? map : null);
diff --git a/src/ol/interaction/keyboardpaninteraction.js b/src/ol/interaction/keyboardpaninteraction.js
index a9154fbf0d..0caeb267ba 100644
--- a/src/ol/interaction/keyboardpaninteraction.js
+++ b/src/ol/interaction/keyboardpaninteraction.js
@@ -85,7 +85,7 @@ ol.interaction.KeyboardPan.handleEvent = function(mapBrowserEvent) {
         keyCode == goog.events.KeyCodes.UP)) {
       var map = mapBrowserEvent.map;
       var view = map.getView();
-      goog.asserts.assert(!goog.isNull(view), 'view should not be null');
+      goog.asserts.assert(view, 'map must have view');
       var mapUnitsDelta = view.getResolution() * this.pixelDelta_;
       var deltaX = 0, deltaY = 0;
       if (keyCode == goog.events.KeyCodes.DOWN) {
diff --git a/src/ol/interaction/keyboardzoominteraction.js b/src/ol/interaction/keyboardzoominteraction.js
index 9245d07191..75e48f0d1a 100644
--- a/src/ol/interaction/keyboardzoominteraction.js
+++ b/src/ol/interaction/keyboardzoominteraction.js
@@ -77,7 +77,7 @@ ol.interaction.KeyboardZoom.handleEvent = function(mapBrowserEvent) {
       var delta = (charCode == '+'.charCodeAt(0)) ? this.delta_ : -this.delta_;
       map.render();
       var view = map.getView();
-      goog.asserts.assert(!goog.isNull(view), 'view should not be null');
+      goog.asserts.assert(view, 'map must have view');
       ol.interaction.Interaction.zoomByDelta(
           map, view, delta, undefined, this.duration_);
       mapBrowserEvent.preventDefault();
diff --git a/src/ol/interaction/modifyinteraction.js b/src/ol/interaction/modifyinteraction.js
index 30fe563394..f850f63a4a 100644
--- a/src/ol/interaction/modifyinteraction.js
+++ b/src/ol/interaction/modifyinteraction.js
@@ -243,7 +243,7 @@ ol.interaction.Modify.prototype.addFeature_ = function(feature) {
     this.SEGMENT_WRITERS_[geometry.getType()].call(this, feature, geometry);
   }
   var map = this.getMap();
-  if (!goog.isNull(map)) {
+  if (map) {
     this.handlePointerAtPixel_(this.lastPixel_, map);
   }
   goog.events.listen(feature, goog.events.EventType.CHANGE,
@@ -259,8 +259,7 @@ ol.interaction.Modify.prototype.removeFeature_ = function(feature) {
   this.removeFeatureSegmentData_(feature);
   // Remove the vertex feature if the collection of canditate features
   // is empty.
-  if (!goog.isNull(this.vertexFeature_) &&
-      this.features_.getLength() === 0) {
+  if (this.vertexFeature_ && this.features_.getLength() === 0) {
     this.overlay_.getSource().removeFeature(this.vertexFeature_);
     this.vertexFeature_ = null;
   }
@@ -501,7 +500,7 @@ ol.interaction.Modify.prototype.writeGeometryCollectionGeometry_ =
 ol.interaction.Modify.prototype.createOrUpdateVertexFeature_ =
     function(coordinates) {
   var vertexFeature = this.vertexFeature_;
-  if (goog.isNull(vertexFeature)) {
+  if (!vertexFeature) {
     vertexFeature = new ol.Feature(new ol.geom.Point(coordinates));
     this.vertexFeature_ = vertexFeature;
     this.overlay_.getSource().addFeature(vertexFeature);
@@ -534,7 +533,7 @@ ol.interaction.Modify.handleDownEvent_ = function(evt) {
   this.handlePointerAtPixel_(evt.pixel, evt.map);
   this.dragSegments_ = [];
   var vertexFeature = this.vertexFeature_;
-  if (!goog.isNull(vertexFeature)) {
+  if (vertexFeature) {
     var insertVertices = [];
     var geometry = /** @type {ol.geom.Point} */ (vertexFeature.getGeometry());
     var vertex = geometry.getCoordinates();
@@ -584,7 +583,7 @@ ol.interaction.Modify.handleDownEvent_ = function(evt) {
         new ol.interaction.ModifyEvent(ol.ModifyEventType.MODIFYSTART,
         this.features_, evt));
   }
-  return !goog.isNull(this.vertexFeature_);
+  return this.vertexFeature_ !== null;
 };
 
 
@@ -678,8 +677,7 @@ ol.interaction.Modify.handleEvent = function(mapBrowserEvent) {
       !this.handlingDownUpSequence) {
     this.handlePointerMove_(mapBrowserEvent);
   }
-  if (!goog.isNull(this.vertexFeature_) &&
-      this.deleteCondition_(mapBrowserEvent)) {
+  if (this.vertexFeature_ && this.deleteCondition_(mapBrowserEvent)) {
     if (mapBrowserEvent.type != ol.MapBrowserEvent.EventType.SINGLECLICK ||
         !this.ignoreNextSingleClick_) {
       var geometry = this.vertexFeature_.getGeometry();
@@ -768,7 +766,7 @@ ol.interaction.Modify.prototype.handlePointerAtPixel_ = function(pixel, map) {
       return;
     }
   }
-  if (!goog.isNull(this.vertexFeature_)) {
+  if (this.vertexFeature_) {
     this.overlay_.getSource().removeFeature(this.vertexFeature_);
     this.vertexFeature_ = null;
   }
@@ -940,7 +938,7 @@ ol.interaction.Modify.prototype.removeVertex_ = function() {
             newSegmentData);
         this.updateSegmentIndices_(geometry, index, segmentData.depth, -1);
 
-        if (!goog.isNull(this.vertexFeature_)) {
+        if (this.vertexFeature_) {
           this.overlay_.getSource().removeFeature(this.vertexFeature_);
           this.vertexFeature_ = null;
         }
diff --git a/src/ol/interaction/mousewheelzoominteraction.js b/src/ol/interaction/mousewheelzoominteraction.js
index d906967b21..2c596921ce 100644
--- a/src/ol/interaction/mousewheelzoominteraction.js
+++ b/src/ol/interaction/mousewheelzoominteraction.js
@@ -117,7 +117,7 @@ ol.interaction.MouseWheelZoom.prototype.doZoom_ = function(map) {
   var delta = ol.math.clamp(this.delta_, -maxDelta, maxDelta);
 
   var view = map.getView();
-  goog.asserts.assert(!goog.isNull(view), 'view should not be null');
+  goog.asserts.assert(view, 'map must have view');
 
   map.render();
   ol.interaction.Interaction.zoomByDelta(map, view, -delta, this.lastAnchor_,
diff --git a/src/ol/interaction/snapinteraction.js b/src/ol/interaction/snapinteraction.js
index c224d85c43..3b71c0d4ad 100644
--- a/src/ol/interaction/snapinteraction.js
+++ b/src/ol/interaction/snapinteraction.js
@@ -205,9 +205,9 @@ ol.interaction.Snap.prototype.forEachFeatureRemove_ = function(feature) {
  */
 ol.interaction.Snap.prototype.getFeatures_ = function() {
   var features;
-  if (!goog.isNull(this.features_)) {
+  if (this.features_) {
     features = this.features_;
-  } else if (!goog.isNull(this.source_)) {
+  } else if (this.source_) {
     features = this.source_.getFeatures();
   }
   goog.asserts.assert(features !== undefined, 'features should be defined');
@@ -328,12 +328,12 @@ ol.interaction.Snap.prototype.setMap = function(map) {
   goog.base(this, 'setMap', map);
 
   if (map) {
-    if (!goog.isNull(this.features_)) {
+    if (this.features_) {
       keys.push(this.features_.on(ol.CollectionEventType.ADD,
           this.handleFeatureAdd_, this));
       keys.push(this.features_.on(ol.CollectionEventType.REMOVE,
           this.handleFeatureRemove_, this));
-    } else if (!goog.isNull(this.source_)) {
+    } else if (this.source_) {
       keys.push(this.source_.on(ol.source.VectorEventType.ADDFEATURE,
           this.handleFeatureAdd_, this));
       keys.push(this.source_.on(ol.source.VectorEventType.REMOVEFEATURE,
diff --git a/src/ol/interaction/translateinteraction.js b/src/ol/interaction/translateinteraction.js
index 50642851d8..d95fc0adc5 100644
--- a/src/ol/interaction/translateinteraction.js
+++ b/src/ol/interaction/translateinteraction.js
@@ -61,7 +61,7 @@ goog.inherits(ol.interaction.Translate, ol.interaction.Pointer);
  */
 ol.interaction.Translate.handleDownEvent_ = function(event) {
   this.lastFeature_ = this.featuresAtPixel_(event.pixel, event.map);
-  if (goog.isNull(this.lastCoordinate_) && !goog.isNull(this.lastFeature_)) {
+  if (!this.lastCoordinate_ && this.lastFeature_) {
     this.lastCoordinate_ = event.coordinate;
     ol.interaction.Translate.handleMoveEvent_.call(this, event);
     return true;
@@ -77,7 +77,7 @@ ol.interaction.Translate.handleDownEvent_ = function(event) {
  * @private
  */
 ol.interaction.Translate.handleUpEvent_ = function(event) {
-  if (!goog.isNull(this.lastCoordinate_)) {
+  if (this.lastCoordinate_) {
     this.lastCoordinate_ = null;
     ol.interaction.Translate.handleMoveEvent_.call(this, event);
     return true;
@@ -92,18 +92,18 @@ ol.interaction.Translate.handleUpEvent_ = function(event) {
  * @private
  */
 ol.interaction.Translate.handleDragEvent_ = function(event) {
-  if (!goog.isNull(this.lastCoordinate_)) {
+  if (this.lastCoordinate_) {
     var newCoordinate = event.coordinate;
     var deltaX = newCoordinate[0] - this.lastCoordinate_[0];
     var deltaY = newCoordinate[1] - this.lastCoordinate_[1];
 
-    if (!goog.isNull(this.features_)) {
+    if (this.features_) {
       this.features_.forEach(function(feature) {
         var geom = feature.getGeometry();
         geom.translate(deltaX, deltaY);
         feature.setGeometry(geom);
       });
-    } else if (goog.isNull(this.lastFeature_)) {
+    } else if (this.lastFeature_) {
       var geom = this.lastFeature_.getGeometry();
       geom.translate(deltaX, deltaY);
       this.lastFeature_.setGeometry(geom);
@@ -130,7 +130,7 @@ ol.interaction.Translate.handleMoveEvent_ = function(event)
   if (intersectingFeature) {
     var isSelected = false;
 
-    if (!goog.isNull(this.features_) &&
+    if (this.features_ &&
         ol.array.includes(this.features_.getArray(), intersectingFeature)) {
       isSelected = true;
     }
@@ -138,12 +138,12 @@ ol.interaction.Translate.handleMoveEvent_ = function(event)
     this.previousCursor_ = elem.style.cursor;
 
     // WebKit browsers don't support the grab icons without a prefix
-    elem.style.cursor = !goog.isNull(this.lastCoordinate_) ?
+    elem.style.cursor = this.lastCoordinate_ ?
         '-webkit-grabbing' : (isSelected ? '-webkit-grab' : 'pointer');
 
     // Thankfully, attempting to set the standard ones will silently fail,
     // keeping the prefixed icons
-    elem.style.cursor = goog.isNull(this.lastCoordinate_) ?
+    elem.style.cursor = !this.lastCoordinate_ ?
         'grabbing' : (isSelected ? 'grab' : 'pointer');
 
   } else {
@@ -171,7 +171,7 @@ ol.interaction.Translate.prototype.featuresAtPixel_ = function(pixel, map) {
         return feature;
       });
 
-  if (!goog.isNull(this.features_) &&
+  if (this.features_ &&
       ol.array.includes(this.features_.getArray(), intersectingFeature)) {
     found = intersectingFeature;
   }