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

    Creates a function that checks whether the piped array is a subset of another array. Use it with pipe.

    const result = pipe(array, isSubset(superset));
    Info

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

    Usage

    isSubset returns true when every value in the piped array is present in superset.

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

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

pipe([1, 4], isSubset([1, 2, 3])); // => false

    Parameters

    supersetreadonly T[]required

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

    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.