Type Alias ElementMatch<T, Criteria, Options>

ElementMatch: [T] extends [Criteria]
    ? T
    : TypePlusOptions.Merge<
        Options,
        ArrayPlus.ElementMatch.DefaultOptions<Criteria>,
    > extends infer C extends
        Record<keyof ArrayPlus.ElementMatch.Options, unknown>
        ? (
            T extends Criteria
                ? T
                : C["widen"] extends true
                    ? Criteria extends T ? C["$widen"] : C["$notMatch"]
                    : C["$notMatch"]
        ) extends infer R
            ? IsUnion<
                T,
                IsNever<R, { $else: R | C["$unionNotMatch"]; $then: R }>,
                R,
            >
            : C["$notMatch"]
        : never

🦴 utilities 🔢 customizable

Filter the element T in an array or tuple to match Criteria.

Type Parameters

T
Criteria
Options extends ArrayPlus.ElementMatch.Options = ArrayPlus.ElementMatch.DefaultOptions<Criteria>

Type Param: Options['widen']

Allow using narrow type to match widen type. e.g. number, 1 -> 1 | undefined. Default to true.

Type Param: Options['$notMatch']

Return value when T does not match Criteria. Default to never.

Type Param: Options['$widen']

Return value when widen is true. Default to Criteria | undefined.

Type Param: Options['$unionNotMatch']

Return value when a branch of the union T does not match Criteria. Default to never.

If you want the type to behave more like JavaScript, you can override it to return undefined.

Since it is a union, the result will be joined to the matched branch as union. e.g. ElementMatch<1 | 2, 1> -> 1 | undefined