From df590588125e5a8e362ed35f1c4acf46f8499977 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Wed, 13 Jul 2016 11:47:53 -0700
Subject: [PATCH] Fix endsWith bug

---
 src/compiler/utilities.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 4a8391338c..f970a94373 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -3120,6 +3120,6 @@ namespace ts {
 
     export function endsWith(str: string, suffix: string): boolean {
         const expectedPos = str.length - suffix.length;
-        return str.indexOf(suffix, expectedPos) === expectedPos;
+        return expectedPos >= 0 && str.indexOf(suffix, expectedPos) === expectedPos;
     }
 }