diff --git a/src/ol/feature.js b/src/ol/feature.js
index bdd0d888d1..84620e797f 100644
--- a/src/ol/feature.js
+++ b/src/ol/feature.js
@@ -294,7 +294,7 @@ ol.Feature.prototype.setGeometryName = function(name) {
 ol.Feature.createStyleFunction = function(obj) {
   var styleFunction;
 
-  if (goog.isFunction(obj)) {
+  if (typeof obj === 'function') {
     styleFunction = obj;
   } else {
     /**
diff --git a/src/ol/featureloader.js b/src/ol/featureloader.js
index 66cc5c7b5e..341d8c87a0 100644
--- a/src/ol/featureloader.js
+++ b/src/ol/featureloader.js
@@ -31,7 +31,7 @@ ol.featureloader.loadFeaturesXhr = function(url, format, success, failure) {
       function(extent, resolution, projection) {
         var xhr = new XMLHttpRequest();
         xhr.open('GET',
-            goog.isFunction(url) ? url(extent, resolution, projection) : url,
+            typeof url === 'function' ? url(extent, resolution, projection) : url,
             true);
         if (format.getType() == ol.format.FormatType.ARRAY_BUFFER) {
           xhr.responseType = 'arraybuffer';
diff --git a/src/ol/interaction/selectinteraction.js b/src/ol/interaction/selectinteraction.js
index 50eecea1f5..9cb3e83caa 100644
--- a/src/ol/interaction/selectinteraction.js
+++ b/src/ol/interaction/selectinteraction.js
@@ -158,7 +158,7 @@ ol.interaction.Select = function(opt_options) {
 
   var layerFilter;
   if (options.layers) {
-    if (goog.isFunction(options.layers)) {
+    if (typeof options.layers === 'function') {
       /**
        * @param {ol.layer.Layer} layer Layer.
        * @return {boolean} Include.
diff --git a/src/ol/interaction/translateinteraction.js b/src/ol/interaction/translateinteraction.js
index d5ea1b9948..9e72fdf334 100644
--- a/src/ol/interaction/translateinteraction.js
+++ b/src/ol/interaction/translateinteraction.js
@@ -109,7 +109,7 @@ ol.interaction.Translate = function(options) {
 
   var layerFilter;
   if (options.layers) {
-    if (goog.isFunction(options.layers)) {
+    if (typeof options.layers === 'function') {
       /**
        * @param {ol.layer.Layer} layer Layer.
        * @return {boolean} Include.
diff --git a/src/ol/layer/heatmaplayer.js b/src/ol/layer/heatmaplayer.js
index 72517bbb85..e14ae77d0a 100644
--- a/src/ol/layer/heatmaplayer.js
+++ b/src/ol/layer/heatmaplayer.js
@@ -101,7 +101,7 @@ ol.layer.Heatmap = function(opt_options) {
   } else {
     weightFunction = weight;
   }
-  goog.asserts.assert(goog.isFunction(weightFunction),
+  goog.asserts.assert(typeof weightFunction === 'function',
       'weightFunction should be a function');
 
   this.setStyle(function(feature, resolution) {
diff --git a/src/ol/layer/vectorlayer.js b/src/ol/layer/vectorlayer.js
index e12da679ab..58e9e1c70b 100644
--- a/src/ol/layer/vectorlayer.js
+++ b/src/ol/layer/vectorlayer.js
@@ -35,7 +35,7 @@ ol.layer.Vector = function(opt_options) {
 
   goog.asserts.assert(
       options.renderOrder === undefined || !options.renderOrder ||
-      goog.isFunction(options.renderOrder),
+      typeof options.renderOrder === 'function',
       'renderOrder must be a comparator function');
 
   var baseOptions = ol.object.assign({}, options);
@@ -161,7 +161,7 @@ ol.layer.Vector.prototype.getUpdateWhileInteracting = function() {
 ol.layer.Vector.prototype.setRenderOrder = function(renderOrder) {
   goog.asserts.assert(
       renderOrder === undefined || !renderOrder ||
-      goog.isFunction(renderOrder),
+      typeof renderOrder === 'function',
       'renderOrder must be a comparator function');
   this.set(ol.layer.VectorProperty.RENDER_ORDER, renderOrder);
 };
diff --git a/src/ol/style/style.js b/src/ol/style/style.js
index 872ca16800..1412def464 100644
--- a/src/ol/style/style.js
+++ b/src/ol/style/style.js
@@ -156,7 +156,7 @@ ol.style.Style.prototype.getZIndex = function() {
  * @api
  */
 ol.style.Style.prototype.setGeometry = function(geometry) {
-  if (goog.isFunction(geometry)) {
+  if (typeof geometry === 'function') {
     this.geometryFunction_ = geometry;
   } else if (typeof geometry === 'string') {
     this.geometryFunction_ = function(feature) {
@@ -202,7 +202,7 @@ ol.style.Style.prototype.setZIndex = function(zIndex) {
 ol.style.createStyleFunction = function(obj) {
   var styleFunction;
 
-  if (goog.isFunction(obj)) {
+  if (typeof obj === 'function') {
     styleFunction = obj;
   } else {
     /**