Extract<T, U>
Constructs a type by extracting from T all union members assignable to U.
Syntax
Extract<Type, Union>Returns
union type — The union of T members that are assignable to U.
Examples
type T = 'a' | 'b' | 'c';
type Result = Extract<T, 'a' | 'z'>; // 'a'
type Fns = Extract<string | (() => void) | number, Function>;
// () => void
Notes
Defined as the distributive conditional `T extends U ? T : never`. It is the
complement of `Exclude`. Commonly used to narrow a discriminated union to the
members matching a given shape.