effect-io-ai

Package: effect
Module: Array

Array.NonEmptyReadonlyArray

A readonly array guaranteed to have at least one element.

When to use

Use when non-emptiness must be tracked at the type level while preventing mutation. Many Array module functions accept or return this type.

Example (Typing a non-empty array)

import type { Array } from "effect"

const nonEmpty: Array.NonEmptyReadonlyArray<number> = [1, 2, 3]
const head: number = nonEmpty[0] // guaranteed to exist

See

• NonEmptyArray — mutable counterpart
• isReadonlyArrayNonEmpty — narrow a ReadonlyArray to this type

Signature

type readonly [A, ...A[]] = readonly [A, ...Array<A>]

Source

Since v2.0.0