# isNaN
> Test if a value is NaN.
## Usage
```javascript
var isnan = require( '@stdlib/assert/is-nan' );
```
#### isnan( value )
Tests if a `value` is `NaN`.
```javascript
var Number = require( '@stdlib/number/ctor' );
var bool = isnan( NaN );
// returns true
bool = isnan( new Number( NaN ) );
// returns true
bool = isnan( 3.14 );
// returns false
bool = isnan( null );
// returns false
```
#### isnan.isPrimitive( value )
Tests if a `value` is a `NaN` primitive `number`.
```javascript
var Number = require( '@stdlib/number/ctor' );
var bool = isnan.isPrimitive( NaN );
// returns true
bool = isnan.isPrimitive( 3.14 );
// returns false
bool = isnan.isPrimitive( new Number( NaN ) );
// returns false
```
#### isnan.isObject( value )
Tests if a `value` is a `Number` object having a value of `NaN`.
```javascript
var Number = require( '@stdlib/number/ctor' );
var bool = isnan.isObject( NaN );
// returns false
bool = isnan.isObject( new Number( NaN ) );
// returns true
```
## Examples
```javascript
var Number = require( '@stdlib/number/ctor' );
var Symbol = require( '@stdlib/symbol/ctor' );
var isnan = require( '@stdlib/assert/is-nan' );
var bool = isnan( NaN );
// returns true
bool = isnan( new Number( NaN ) );
// returns true
bool = isnan( 5 );
// returns false
bool = isnan( '5' );
// returns false
bool = isnan( null );
// returns false
bool = isnan( Symbol( 'NaN' ) );
// returns false
```