Merge pull request #15694 from astegmaier/patch-1

getOwnPropertyDescriptor return should allow undefined

Author: mhegazy

src/lib/es2015.proxy.d.ts

@@ -3,7 +3,7 @@ interface ProxyHandler<T extends object> {
     setPrototypeOf? (target: T, v: any): boolean;
     isExtensible? (target: T): boolean;
     preventExtensions? (target: T): boolean;
-    getOwnPropertyDescriptor? (target: T, p: PropertyKey): PropertyDescriptor;
+    getOwnPropertyDescriptor? (target: T, p: PropertyKey): PropertyDescriptor | undefined;
     has? (target: T, p: PropertyKey): boolean;
     get? (target: T, p: PropertyKey, receiver: any): any;
     set? (target: T, p: PropertyKey, value: any, receiver: any): boolean;