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/predicate/isNaN.md.
Install massaman

    isNaN

    Checks if a value is NaN.

    isNaN(NaN) // true
isNaN(42) // false

    Usage

    isNaN(value: unknown)

    Checks if a value is NaN.

    import { isNaN } from 'massaman'
// or:  import { isNaN } from 'massaman/predicate'

isNaN(NaN) // true
isNaN(42) // false

    Parameters

    valueunknownrequired

    the value to test.

    Returns

    whether value is the numeric NaN value; a true result narrows it to number.

    value is number