effect-io-ai

Package: effect
Module: Array

Array.matchRight

Pattern-matches on an array from the right, providing all elements except the last and the last element separately.

When to use

Use when you need to branch on an array and handle the non-empty case as the elements before the last plus the last element.

Details

onNonEmpty receives (init, last) where init is everything but the last element.

Example (Destructuring init and last)

import { Array } from "effect"

const matchRight = Array.matchRight({
  onEmpty: () => "empty",
  onNonEmpty: (init, last) => `init: ${init.length}, last: ${last}`
})
console.log(matchRight([])) // "empty"
console.log(matchRight([1, 2, 3])) // "init: 2, last: 3"

See

• match — receives the full non-empty array
• matchLeft — destructures into head + tail

Signature

declare const matchRight: { <B, A, C = B>(options: { readonly onEmpty: LazyArg<B>; readonly onNonEmpty: (init: Array<A>, last: A) => C; }): (self: ReadonlyArray<A>) => B | C; <A, B, C = B>(self: ReadonlyArray<A>, options: { readonly onEmpty: LazyArg<B>; readonly onNonEmpty: (init: Array<A>, last: A) => C; }): B | C; }

Source

Since v2.0.0