Type Alias Find<A, Criteria, Options>

Find<A, Criteria, Options>: TypePlusOptions.Merge<Options, TuplePlus.Find.DefaultOptions<Criteria>> extends infer O extends TuplePlus.Find.Options
    ? IsTuple<A, {
        $else: O["$array"];
        $then: A["length"] extends 0
            ? O["$emptyTuple"]
            : TuplePlus.Find.Device<A, Criteria, O>;
    }>
    : never

🦴 utilities 🔢 customizable

Find the first type in tuple A that matches Criteria.

Type Parameters

A extends readonly unknown[]
Criteria
Options extends TuplePlus.Find.Options = TuplePlus.Find.DefaultOptions<Criteria>

Example

type R = TuplePlus.Find<[true, 1, 'x', 3], string> // 'x'
type R = TuplePlus.Find<[true, 1, 'x', 3], number> // 1
type R = TuplePlus.Find<[string, number, 1], 1> // widen: 1 | undefined
type R = TuplePlus.Find<[true, number | string], string> // unionMiss: string | undefined

type R = TuplePlus.Find<[true, 1, 'x'], 2> // never

Type Param: Options['widen']

performs widen match. Default to true. With widen match, a narrowed type will match its widen type. e.g. matching 1 against number yields 1 | undefined

The widen behavior can be customized by Options['$widen']

Type Param: Options['$array']

return type when A is an array. Default to not supported message.

Type Param: Options['caseEmptyTuple']

return type when A is an empty tuple. Default to never.

Type Param: Options['$never']

return type when A is never. Default to never.

Type Param: Options['$notMatch']

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

Type Param: Options['$widen']

return type when T in A is a widen type of Criteria. Default to Criteria | undefined. Set it to never for a more type-centric behavior

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.