diff --git a/es6.d.ts b/es6.d.ts
index bba5f4665..0c7324ccf 100644
--- a/es6.d.ts
+++ b/es6.d.ts
@@ -1 +1,9 @@
-declare var Symbol: any;
\ No newline at end of file
+declare var Symbol: any;
+
+interface ObjectConstructor {
+    assign(target: any, ...sources: any[]): any;
+    is(value1: any, value2: any): boolean;
+    setPrototypeOf(o: any, proto: any): any;
+}
+
+declare var Object: ObjectConstructor;
\ No newline at end of file