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.

Try it

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.

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® 2027 Language Specification
# sec-number.nan

Browser compatibility

desktop mobile server
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Bun
Deno
Node.js
NaN
Chrome – Full support
Chrome 1 (Release date: 2008-12-11)
footnote Full support
Edge – Full support
Edge 12 (Release date: 2015-07-29)
footnote Full support
Firefox – Full support
Firefox 1 (Release date: 2004-11-09)
footnote Full support
Opera – Full support
Opera 3 (Release date: 1997-12-01)
footnote Full support
Safari – Full support
Safari 1 (Release date: 2003-06-23)
footnote Full support
Chrome Android – Full support
Chrome Android 18 (Release date: 2012-06-27)
footnote Full support
Firefox for Android – Full support
Firefox for Android 4 (Release date: 2011-03-29)
footnote Full support
Opera Android – Full support
Opera Android 10.1 (Release date: 2010-11-09)
footnote Full support
Safari on iOS – Full support
Safari on iOS 1 (Release date: 2007-06-29)
footnote Full support
Samsung Internet – Full support
Samsung Internet 1 (Release date: 2013-04-27)
footnote Full support
WebView Android – Full support
WebView Android 4.4 (Release date: 2013-12-09)
footnote Full support
WebView on iOS – Full support
WebView on iOS 1 (Release date: 2007-06-29)
footnote Full support
Bun – Full support
Bun 1 (Release date: 2023-09-08)
footnote Full support
Deno – Full support
Deno 1 (Release date: 2020-05-13)
footnote Full support
Node.js – Full support
Node.js 0.10 (Release date: 2013-03-11)
footnote Full support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support

See also