ArrayLength.md

typelab / utils / ArrayLength

type ArrayLength<T> = T extends ReadonlyArray ? _IfNotAnyOrNever<T, T["length"]> : never;

Extracts the length of an Array type.

Type Parameters

Type Parameter	Description
T	The target Array.

Returns

The length of type T.

Example

type Length = ArrayLength<[1, 2, 3]>; // 3
type Length2 = ArrayLength<string[]>; // number
type Never = ArrayLength<any>; // never