effect-io-ai

Package: effect
Module: Array

Array.findFirstWithIndex

Returns the first selected value together with its index, wrapped in an Option.

When to use

Use to find both the first matching element and its index in one pass.

Details

Accepts a predicate, a refinement, or a function returning Option. For an Option-returning function, returns [mappedValue, index] for the first Some, or Option.none() if no element is selected.

Example (Finding element with its index)

import { Array } from "effect"

console.log(Array.findFirstWithIndex([1, 2, 3, 4, 5], (x) => x > 3)) // Option.some([4, 3])

See

• findFirst — get only the element
• findFirstIndex — get only the index

Signature

declare const findFirstWithIndex: { <A, B>(f: (a: NoInfer<A>, i: number) => Option.Option<B>): (self: Iterable<A>) => Option.Option<[B, number]>; <A, B extends A>(refinement: (a: NoInfer<A>, i: number) => a is B): (self: Iterable<A>) => Option.Option<[B, number]>; <A>(predicate: (a: NoInfer<A>, i: number) => boolean): (self: Iterable<A>) => Option.Option<[A, number]>; <A, B>(self: Iterable<A>, f: (a: A, i: number) => Option.Option<B>): Option.Option<[B, number]>; <A, B extends A>(self: Iterable<A>, refinement: (a: A, i: number) => a is B): Option.Option<[B, number]>; <A>(self: Iterable<A>, predicate: (a: A, i: number) => boolean): Option.Option<[A, number]>; }

Source

Since v3.17.0