javascript static data property

Number.NaN

The Number.NaN static data property represents Not-A-Number, which is equivalent to NaN. For more information about the behaviors of NaN, see the description for the global property.

Interactive exampleOpen the canonical MDN source to run this embedded demo.

function clean(x) {
  if (x === Number.NaN) {
    // Can never be true
    return null;
  }
  if (isNaN(x)) {
    return 0;
  }
}

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

Value

The number value NaN.

0

Description

Because NaN is a static property of Number, you always use it as Number.NaN, rather than as a property of a number value.

Examples

Checking whether values are numeric

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

Specifications

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.