# isnan [![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] > Test if a double-precision floating-point numeric value is NaN.

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

## 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 ```

## Examples ```javascript var isnan = require( '@stdlib/math-base-assert-is-nan' ); var bool = isnan( NaN ); // returns true bool = isnan( 5.0 ); // returns false ```

* * * ## See Also - [`@stdlib/math/base/assert/is-nanf`][@stdlib/math/base/assert/is-nanf]: test if a single-precision floating-point numeric value is NaN.

* * * ## 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 © 2016-2022. The Stdlib [Authors][stdlib-authors].

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