For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt, and this page is available as Markdown at /reference/fp/differenceWith.md.
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    differenceWith (Functional Programming) es-toolkit

    Creates a function that excludes values using a custom equality function. Use it with pipe.

    const result = pipe(array, differenceWith(secondArray, areItemsEqual));
    Info

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

    Usage

    differenceWith keeps values from the piped array only when areItemsEqual returns false for every value in secondArray.

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

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

    Parameters

    secondArrayreadonly U[]required

    The array containing values to compare against.

    areItemsEqual(item: T, other: U) => booleanrequired

    The function that decides whether two values are equal.

    Returns

    A function that maps a readonly T[] to values not matched by the comparator.

    (array: readonly T[]) => T[]
    Source: es-toolkit

    Re-exported verbatim from es-toolkit. Implementation, edge cases, and performance behavior are owned upstream. This page mirrors the documentation at the pinned version; the linked source is authoritative.