IsUndefinable.md

typelab / assertions / IsUndefinable

type IsUndefinable<T> = IfUndefinable<T, true, false>;

Checks if a given type T has undefined type.

Type Parameters

Type Parameter	Description
T	The type to be checked.

Returns

true if T has undefined type, false otherwise.

Example

type Valid = IsUndefinable<string | undefined>; // true
type Invalid = IsUndefinable<string>; // false