effect-io-ai

Package: effect
Module: Array

Array.modify

Applies a function to the element at the specified index safely, returning the updated array in Option.some.

When to use

Use to derive a replacement value from an array element at a specific index while leaving the other elements unchanged.

Details

Returns Option.none() when the index is out of bounds.

Example (Modifying an element)

import { Array } from "effect"

console.log(Array.modify([1, 2, 3, 4], 2, (n) => n * 2)) // Option.some([1, 2, 6, 4])
console.log(Array.modify([1, 2, 3, 4], 5, (n) => n * 2)) // Option.none()

See

• replace — set a fixed value at an index
• modifyHeadNonEmpty — modify the first element
• modifyLastNonEmpty — modify the last element

Signature

declare const modify: { <A, B, S extends Iterable<A> = Iterable<A>>(i: number, f: (a: ReadonlyArray.Infer<S>) => B): (self: S) => Option.Option<ReadonlyArray.With<S, ReadonlyArray.Infer<S> | B>>; <A, B, S extends Iterable<A> = Iterable<A>>(self: S, i: number, f: (a: ReadonlyArray.Infer<S>) => B): Option.Option<ReadonlyArray.With<S, ReadonlyArray.Infer<S> | B>>; }

Source

Since v2.0.0