# isInfinite > Test if a double-precision floating-point numeric value is infinite.
## Usage ```javascript var isInfinite = require( '@stdlib/math/base/assert/is-infinite' ); ``` #### isInfinite( x ) Tests if a double-precision floating-point `numeric` value is infinite. ```javascript var bool = isInfinite( Infinity ); // returns true bool = isInfinite( -Infinity ); // returns true ```
## Examples ```javascript var PINF = require( '@stdlib/constants/float64/pinf' ); var NINF = require( '@stdlib/constants/float64/ninf' ); var isInfinite = require( '@stdlib/math/base/assert/is-infinite' ); var bool = isInfinite( PINF ); // returns true bool = isInfinite( NINF ); // returns true bool = isInfinite( 5.0 ); // returns false bool = isInfinite( NaN ); // returns false ```