Number.NaN

Baseline

20157

Number.NaN (Not-A-Number) NaN NaN

function clean(x) {
  if (x === Number.NaN) {
    // true 
    return null;
  }
  if (isNaN(x)) {
    return 0;
  }
}

console.log(clean(Number.NaN));
// : 0

NaN

`Number.NaN`

NaN Number Number.NaN

function sanitize(x) {
  if (isNaN(x)) {
    return Number.NaN;
  }
  return x;
}


ECMAScript 2027 LanguageSpecification # sec-number.nan

NaN
Number.isNaN()

MDN

MDN 2025826

GitHub

Number
1. Number()
Object/Function
1. __proto__
2. constructor