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/isSubsetWith.md.
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    isSubsetWith (Functional Programming) es-toolkit

    Creates a function that checks subset membership using a custom equality function. Use it with pipe.

    const result = pipe(array, isSubsetWith(superset, areItemsEqual));
    Info

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

    Usage

    isSubsetWith returns true when every value in the piped array matches at least one value in superset according to areItemsEqual.

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

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

    Parameters

    supersetreadonly T[]required

    The array that may contain all values from the piped array.

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

    The function that decides whether two values are equal.

    Returns

    A function that maps a readonly T[] to whether it is a subset.

    (array: readonly T[]) => boolean
    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.