See the MDN section on "confusing special case behavior"[1] for why they probably didn't want to use the global version of isNaN. Number.isNaN handles those cas

See the MDN section on "confusing special case behavior"[1] for why they probably didn't want to use the global version of isNaN. Number.isNaN handles those cases better but is not as widely supported. [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isNaN#confusing_special-case_behavior https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...