diff --git a/Foundation/CPArray+KVO.j b/Foundation/CPArray+KVO.j
index 50a93479e..395e0fd59 100644
--- a/Foundation/CPArray+KVO.j
+++ b/Foundation/CPArray+KVO.j
@@ -362,7 +362,7 @@
 
 - (id)valueForKeyPath:(CPString)aKeyPath
 {
-    if (aKeyPath.indexOf("@") === 0)
+    if (aKeyPath.charAt(0) === "@")
     {
         var dotIndex = aKeyPath.indexOf("."),
             operator,