Type Alias IsType<T, U>

IsType: T extends U ? true : false

Type guard: detect whether a type T extends type U.

Type Parameters

T
Type to test
U
Target type

Remarks

Resolves to true if T is assignable to U, otherwise false.

Example

type A = IsType< string, string | number >;  // true
type B = IsType< number, string >;           // false