Number.NaN

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

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.

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Value

The number value NaN.

Property attributes of Number.NaN
Writableno
Enumerableno
Configurableno

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

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

Specifications

Specification
ECMAScript Language Specification
# sec-number.nan

Browser compatibility

BCD tables only load in the browser

See also