Type Alias Cast<T, U>

Cast: T extends U ? T : U

Cast a type while preserving assignability.

Type Parameters

T
Source type
U
Target type

Remarks

Keeps the source type if it is assignable to the target type; otherwise, resolves to the target type.

Example

type A = Cast< string, string | number >;   // string
type B = Cast< number, string | number >;   // number
type C = Cast< boolean, string | number >;  // string | number