diff --git a/src/js/utils.js b/src/js/utils.js
index 970b72fe9..709937524 100644
--- a/src/js/utils.js
+++ b/src/js/utils.js
@@ -373,8 +373,11 @@
     lookup: function(key) {
         var value = this.map.get(key);
         if ( value !== undefined && this.array[0] !== key ) {
-            this.array.splice(this.array.indexOf(key), 1);
-            this.array.unshift(key);
+            var i = this.array.indexOf(key);
+            do {
+                this.array[i] = this.array[i-1];
+            } while ( --i );
+            this.array[0] = key;
         }
         return value;
     },