From 2aba29fc32b21cd9f56ea8510c37772735ebcadf Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Fri, 9 Feb 2018 14:22:46 -0800
Subject: [PATCH] Add Exclude, Extract, NonNullable, ReturnType, and
 InstanceType types

---
 src/lib/es5.d.ts | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/src/lib/es5.d.ts b/src/lib/es5.d.ts
index 707f749e365..0f773e78786 100644
--- a/src/lib/es5.d.ts
+++ b/src/lib/es5.d.ts
@@ -1338,6 +1338,31 @@ type Record<K extends string, T> = {
     [P in K]: T;
 };
 
+/**
+ * Exclude from T those types that are assignable to U
+ */
+type Exclude<T, U> = T extends U ? never : T;
+
+/**
+ * Extract from T those types that are assignable to U
+ */
+type Extract<T, U> = T extends U ? T : never;
+
+/**
+ * Exclude null and undefined from T
+ */
+type NonNullable<T> = T extends null | undefined ? never : T;
+
+/**
+ * Obtain the return type of a function type
+ */
+type ReturnType<T extends (...args: any[]) => any> = T extends (...args: any[]) => infer R ? R : any;
+
+/**
+ * Obtain the return type of a constructor function type
+ */
+type InstanceType<T extends new (...args: any[]) => any> = T extends new (...args: any[]) => infer R ? R : any;
+
 /**
  * Marker for contextual 'this' type
  */