uniqWith (Functional Programming)

Creates a function that removes duplicates using a custom equality function. Use it with pipe.

const result = pipe(array, uniqWith(areItemsEqual));

::: info

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

:::

Usage

uniqWith keeps the first value that does not match a previously kept value according to areItemsEqual. It is lazy-capable inside pipe.

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

pipe(
  [{ id: 1 }, { id: 1 }, { id: 2 }],
  uniqWith((a, b) => a.id === b.id)
); // => [{ id: 1 }, { id: 2 }]

Parameters

• areItemsEqual ((item: T, other: T) => boolean): The function that decides whether two values are equal.

Returns

((array: readonly T[]) => T[]): A function that maps a readonly T[] to a duplicate-free array by custom equality.