# isnanf > Test if a single-precision floating-point numeric value is NaN.
## Usage ```javascript var isnanf = require( '@stdlib/math/base/assert/is-nanf' ); ``` #### isnanf( x ) Tests if a single-precision floating-point `numeric` value is `NaN`. ```javascript var bool = isnanf( NaN ); // returns true ```
## Examples ```javascript var isnanf = require( '@stdlib/math/base/assert/is-nanf' ); var bool = isnanf( NaN ); // returns true bool = isnanf( 5.0 ); // returns false ```