# isComplex > Test if a value is a [64-bit][@stdlib/complex/float32] or [128-bit][@stdlib/complex/float64] complex number.
## Usage ```javascript var isComplex = require( '@stdlib/assert/is-complex' ); ``` #### isComplex( value ) Tests if a value is a [64-bit][@stdlib/complex/float32] or [128-bit][@stdlib/complex/float64] complex number. ```javascript var Complex128 = require( '@stdlib/complex/float64' ); var Complex64 = require( '@stdlib/complex/float32' ); var x = new Complex128( 1.0, 3.0 ); var bool = isComplex( x ); // returns true x = new Complex64( 3.0, 1.0 ); bool = isComplex( x ); // returns true ```
## Examples ```javascript var Complex64 = require( '@stdlib/complex/float32' ); var Complex128 = require( '@stdlib/complex/float64' ); var isComplex = require( '@stdlib/assert/is-complex' ); var out = isComplex( new Complex64( 2.0, 2.0 ) ); // returns true out = isComplex( new Complex128( 3.0, 1.0 ) ); // returns true out = isComplex( {} ); // returns false out = isComplex( null ); // returns false ```