diff --git a/src/ol/proj/proj.js b/src/ol/proj/proj.js
index dbfa0e1c26..b824164ddf 100644
--- a/src/ol/proj/proj.js
+++ b/src/ol/proj/proj.js
@@ -597,8 +597,7 @@ ol.proj.removeTransform = function(source, destination) {
       'destinationCode should be in transforms of sourceCode');
   var transform = transforms[sourceCode][destinationCode];
   delete transforms[sourceCode][destinationCode];
-  var keys = goog.object.getKeys(transforms[sourceCode]);
-  if (keys.length === 0) {
+  if (goog.object.isEmpty(transforms[sourceCode])) {
     delete transforms[sourceCode];
   }
   return transform;