npm package: @stdlib/math-base-assert-is-nan
Description: Test if a double-precision floating-point numeric value is NaN.
Author: The Stdlib Authors
Latest version: 0.2.3

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# isnan

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> Test if a double-precision floating-point numeric value is NaN.

<section class="installation">

## Installation

```bash
npm install @stdlib/math-base-assert-is-nan
```

</section>

<section class="usage">

## Usage

```javascript
var isnan = require( '@stdlib/math-base-assert-is-nan' );
```

#### isnan( x )

Tests if a double-precision floating-point `numeric` value is `NaN`.

```javascript
var bool = isnan( NaN );
// returns true
```

</section>

<!-- /.usage -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var isnan = require( '@stdlib/math-base-assert-is-nan' );

var bool = isnan( NaN );
// returns true

bool = isnan( 5.0 );
// returns false
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/math-base/assert/is-nanf`][@stdlib/math/base/assert/is-nanf]</span><span class="delimiter">: </span><span class="description">test if a single-precision floating-point numeric value is NaN.</span>

</section>

<!-- /.related -->

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<section class="main-repo" >

* * *

## Notice

This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

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<!-- <related-links> -->

[@stdlib/math/base/assert/is-nanf]: https://www.npmjs.com/package/@stdlib/math-base-assert-is-nanf

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</section>

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