isNaN

Tencent IMWeb Frontend Team

Jul 16, 2017 · Frontend Development

Why Does JavaScript Return NaN? Understanding NaN and isNaN()

This article explains the special NaN value in ECMAScript, its two unusual properties, how division by zero yields NaN, and demonstrates the behavior of the isNaN() function with various inputs, including numbers, strings, booleans, and objects, illustrating conversion rules and pitfalls.