Method toBeNaN

packages/expect/src/types.ts:193–193

* Used to check that a variable is NaN.

()

   * Used to check that a variable is NaN.
   */
  toBeNaN(): R;
  /**
   * This is the same as `.toBe(null)` but the error messages are a bit nicer.
   * So use `.toBeNull()` when you want to check that something is null.