mapAtOrElse

function Array.mapAtOrElse<T, U>(
    target: readonly T[],
    idx: number,
    map: (
        value: NoInfer<T>,
        index: number,
        target: readonly NoInfer<T>[],
    ) => T,
    orElse: (target: readonly NoInfer<T>[]) => U,
): readonly T[] | U

Applies the mapper function to the element at the specified index in array, returning a new array with the mapped element, or the result of calling callback with the array if the index is out of bounds.

Example

data-first

import { Array } from "@monstermann/array";

Array.mapAtOrElse(
    [1, 2, 3],
    10,
    (x) => x * 10,
    (arr) => arr.length,
); // 3

data-last

import { Array } from "@monstermann/array";

pipe(
    [1, 2, 3],
    Array.mapAtOrElse(
        10,
        (x) => x * 10,
        (arr) => arr.length,
    ),
); // 3