diff --git a/src/lib/es5.d.ts b/src/lib/es5.d.ts
index f224b095ba40b..0a5f9d9baa257 100644
--- a/src/lib/es5.d.ts
+++ b/src/lib/es5.d.ts
@@ -1586,6 +1586,11 @@ type Extract<T, U> = T extends U ? T : never;
  */
 type Omit<T, K extends keyof any> = Pick<T, Exclude<keyof T, K>>;
 
+/**
+ * Construct a union type from T and null.
+ */
+type Nullable<T> = null | { [P in keyof T]: null | T[P] };
+
 /**
  * Exclude null and undefined from T
  */