ArrayPartial.md

typelab / utils / ArrayPartial

type ArrayPartial<T, Index> = T extends ReadonlyArray<infer Element> ? _IfNotAnyOrNever<T, _IfNotAnyOrNever<Index, _ArrayPartial<T, Index, Element>>> : never;

Extended TypeScript `Partial` to handle Array.

Type Parameters

Type Parameter	Default type	Description
T	‐	The original Array type.
Index	ArrayIndexes<T, true>	The index of T that should be required.

Returns

An Array type with the specified Index set as required.

Example

type Result1 = ArrayPartial<[string, string]>; // [string?, string?]
type Result2 = ArrayPartial<[string, string], 1>; // [string, string?]
type Never1 = ArrayPartial<[string, string], any>; // never
type Never2 = ArrayPartial<any, 1>; // never