JS: Number.isNaN

By Xah Lee. Date: . Last updated: .
Number.isNaN(number)

If number is NaN, return true, else false.

console.assert(Number.isNaN(NaN));

// s------------------------------

console.assert(Number.isNaN("NaN") === false);
console.assert(Number.isNaN("3") === false);
console.assert(Number.isNaN(3) === false);
console.assert(Number.isNaN(Infinity) === false);

What's the difference between global isNaN vs Number.isNaN

The global version converts the argument to number first.