Update definitions

Author: RyanCavanaugh

src/lib/es5.d.ts

@@ -1559,7 +1559,7 @@ type Readonly<T> = {
  * From T, pick a set of properties whose keys are in the union K
  */
 type Pick<T, K extends keyof T> = {
-    [P in K]: T[P];
+    [P in keyof T as K & P]: T[P];
 };
 
 /**
@@ -1582,7 +1582,7 @@ type Extract<T, U> = T extends U ? T : never;
 /**
  * Construct a type with the properties of T except for those in type K.
  */
-type Omit<T, K extends keyof any> = Pick<T, Exclude<keyof T, K>>;
+type Omit<T, K extends keyof any> = { [P in keyof T as Exclude<P, K>]: T[P]; }
 
 /**
  * Exclude null and undefined from T