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Jest · Matcher

toBeNaN

toBeNaN checks whether a value is NaN. Prefix it with .not to check that a value is not NaN.

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Syntax

expect(value).toBeNaN() | expect(value).not.toBeNaN()

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  • expect
  • not
  • toBe
  • toBeFalsy
  • toBeTruthy

Source: Expect · Jest. Checked 2026-11-03.