diff --git a/angularjs/angular.d.ts b/angularjs/angular.d.ts
index 4a9f128223..61d80df3f2 100755
--- a/angularjs/angular.d.ts
+++ b/angularjs/angular.d.ts
@@ -10,7 +10,7 @@ declare var angular: ng.IAngularStatic;
 
 // Support for painless dependency injection
 interface Function {
-    $inject:string[];
+    $inject?: string[];
 }
 
 ///////////////////////////////////////////////////////////////////////////////