diff --git a/framework/core/js/lib/extension-utils.js b/framework/core/js/lib/extension-utils.js
index 373d35d71..862d80bc3 100644
--- a/framework/core/js/lib/extension-utils.js
+++ b/framework/core/js/lib/extension-utils.js
@@ -1,16 +1,17 @@
 export function extend(object, func, extension) {
-  var oldFunc = object[func];
+  var original = object[func];
   object[func] = function() {
     var args = [].slice.apply(arguments);
-    var value = oldFunc.apply(this, args);
-    return extension.apply(this, [value].concat(args));
+    var value = original.apply(this, args);
+    extension.apply(this, [value].concat(args));
+    return value;
   }
 };
 
 export function override(object, func, override) {
-  var parent = object[func];
+  var original = object[func];
   object[func] = function() {
     var args = [].slice.apply(arguments);
-    return override.apply(this, [parent.bind(this)].concat(args));
+    return override.apply(this, [original.bind(this)].concat(args));
   }
-}
+};