Number.NaN

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

{{InteractiveExample("JavaScript Demo: Number.NaN", "taller")}}

```js interactive-example 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 {{jsxref("NaN")}}.

{{js_property_attributes(0, 0, 0)}}

## Description

Because `NaN` is a static property of {{jsxref("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#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• {{jsxref("NaN")}}
• {{jsxref("Number.isNaN()")}}