https://itnext.io/pair-of-concepts-may-confuse-you-in-javascript-number-isnan-and-isnan-556d14448dbb
Medium
Pair of concepts may confuse you in Javascript — Number.isNaN() and isNaN()
With a long history of development (and chaos), JS has some messy legacy that can’t be removed to keep the consistency but only improved by new features/functions. This leads to confusion for…