takeWhile (Functional Programming)

Creates a function that takes leading values while a predicate passes. Use it with pipe.

const result = pipe(array, takeWhile(predicate));

INFO

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

Usage

takeWhile walks the piped array from the beginning and keeps values while predicate returns true. It is lazy-capable and can stop earlier lazy operations inside pipe.

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

pipe(
  [1, 2, 3, 1],
  takeWhile(value => value < 3)
); // => [1, 2]

Parameters

• predicate ((element: T, index: number) => boolean): The function that decides whether a leading value should be kept.

Returns

((array: readonly T[]) => T[]): A function that maps a readonly T[] to the leading values that pass.