union (Functional Programming)

Creates a function that combines two arrays without duplicate values. Use it with pipe.

const result = pipe(array, union(secondArray));

INFO

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

Usage

union returns unique values from the piped array followed by values from secondArray that have not appeared yet.

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

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

Parameters

• secondArray (readonly T[]): The array to combine after the piped array.

Returns

((array: readonly T[]) => T[]): A function that maps a readonly T[] to the union of both arrays.