diff --git a/src/ol/iview.js b/src/ol/iview.js
index 5b7663bd1d..37d828d3e2 100644
--- a/src/ol/iview.js
+++ b/src/ol/iview.js
@@ -25,3 +25,10 @@ ol.IView.prototype.getView2D = function() {
  */
 ol.IView.prototype.getView3D = function() {
 };
+
+
+/**
+ * @return {boolean} Is defined.
+ */
+ol.IView.prototype.isDef = function() {
+};
diff --git a/src/ol/iview2d.js b/src/ol/iview2d.js
index cd3cb188f4..0969e6d696 100644
--- a/src/ol/iview2d.js
+++ b/src/ol/iview2d.js
@@ -59,3 +59,10 @@ ol.IView2D.prototype.getRotation = function() {
  */
 ol.IView2D.prototype.getView2DState = function() {
 };
+
+
+/**
+ * @return {boolean} Is defined.
+ */
+ol.IView2D.prototype.isDef = function() {
+};
diff --git a/src/ol/iview3d.js b/src/ol/iview3d.js
index c74f9acf6b..b54f7d7e42 100644
--- a/src/ol/iview3d.js
+++ b/src/ol/iview3d.js
@@ -8,3 +8,10 @@ goog.provide('ol.IView3D');
  */
 ol.IView3D = function() {
 };
+
+
+/**
+ * @return {boolean} Is defined.
+ */
+ol.IView3D.prototype.isDef = function() {
+};
diff --git a/src/ol/view.js b/src/ol/view.js
index 9d727e3b4d..0bacc4fe3a 100644
--- a/src/ol/view.js
+++ b/src/ol/view.js
@@ -56,6 +56,16 @@ ol.View.prototype.getView2D = goog.abstractMethod;
 ol.View.prototype.getView3D = goog.abstractMethod;
 
 
+/**
+ * @inheritDoc
+ */
+ol.View.prototype.isDef = function() {
+  // FIXME for some reason, we can't use goog.abstractMethod here
+  goog.asserts.fail();
+  return false;
+};
+
+
 /**
  * @param {ol.ViewHint} hint Hint.
  * @param {number} delta Delta.