diff --git a/src/ol/interaction/modifyinteraction.js b/src/ol/interaction/modifyinteraction.js
index a56a212c3d..68b508a039 100644
--- a/src/ol/interaction/modifyinteraction.js
+++ b/src/ol/interaction/modifyinteraction.js
@@ -112,7 +112,7 @@ ol.interaction.Modify = function(options) {
    * @private
    */
   this.overlay_ = new ol.FeatureOverlay({
-    style: (goog.isDef(options.style)) ? options.style :
+    style: goog.isDef(options.style) ? options.style :
         ol.interaction.Modify.getDefaultStyleFunction()
   });
 
diff --git a/src/ol/interaction/selectinteraction.js b/src/ol/interaction/selectinteraction.js
index 545e37f2bf..5c4067e3db 100644
--- a/src/ol/interaction/selectinteraction.js
+++ b/src/ol/interaction/selectinteraction.js
@@ -90,7 +90,7 @@ ol.interaction.Select = function(opt_options) {
    * @type {ol.FeatureOverlay}
    */
   this.featureOverlay_ = new ol.FeatureOverlay({
-    style: (goog.isDef(options.style)) ? options.style :
+    style: goog.isDef(options.style) ? options.style :
         ol.interaction.Select.getDefaultStyleFunction()
   });
 
diff --git a/src/ol/layer/layer.js b/src/ol/layer/layer.js
index ac9d992406..3ce78653d9 100644
--- a/src/ol/layer/layer.js
+++ b/src/ol/layer/layer.js
@@ -62,7 +62,7 @@ ol.layer.Layer.visibleAtResolution = function(layerState, resolution) {
  * @inheritDoc
  */
 ol.layer.Layer.prototype.getLayersArray = function(opt_array) {
-  var array = (goog.isDef(opt_array)) ? opt_array : [];
+  var array = goog.isDef(opt_array) ? opt_array : [];
   array.push(this);
   return array;
 };
@@ -72,7 +72,7 @@ ol.layer.Layer.prototype.getLayersArray = function(opt_array) {
  * @inheritDoc
  */
 ol.layer.Layer.prototype.getLayerStatesArray = function(opt_states) {
-  var states = (goog.isDef(opt_states)) ? opt_states : [];
+  var states = goog.isDef(opt_states) ? opt_states : [];
   states.push(this.getLayerState());
   return states;
 };
diff --git a/src/ol/layer/layergroup.js b/src/ol/layer/layergroup.js
index 1cabc5e843..86dc1042f5 100644
--- a/src/ol/layer/layergroup.js
+++ b/src/ol/layer/layergroup.js
@@ -179,7 +179,7 @@ goog.exportProperty(
  * @inheritDoc
  */
 ol.layer.Group.prototype.getLayersArray = function(opt_array) {
-  var array = (goog.isDef(opt_array)) ? opt_array : [];
+  var array = goog.isDef(opt_array) ? opt_array : [];
   this.getLayers().forEach(function(layer) {
     layer.getLayersArray(array);
   });
@@ -191,7 +191,7 @@ ol.layer.Group.prototype.getLayersArray = function(opt_array) {
  * @inheritDoc
  */
 ol.layer.Group.prototype.getLayerStatesArray = function(opt_states) {
-  var states = (goog.isDef(opt_states)) ? opt_states : [];
+  var states = goog.isDef(opt_states) ? opt_states : [];
 
   var pos = states.length;