head (Functional Programming)

Creates a function that returns the first value of an array. Use it with pipe.

typescript

const result = pipe(array, head());

::: info

Prefer the original es-toolkit head in ordinary code. Use this fp variant when composing transformations with pipe.

:::

Usage

head returns the first value in the piped array. If the array is empty, it returns undefined.

typescript

import { head, pipe } from 'es-toolkit/fp';

pipe([1, 2, 3], head()); // => 1

pipe([], head()); // => undefined

This function takes no arguments; call it as head().

((array: readonly T[]) => T | undefined): A function that maps a readonly T[] to its first value.