# dtype
> Return the data type of a complex number.
## Usage
```javascript
var dtype = require( '@stdlib/complex/dtype' );
```
#### dtype( value )
Returns the [data type][@stdlib/complex/dtypes] of a complex number.
```javascript
var Complex128 = require( '@stdlib/complex/float64/ctor' );
var dt = dtype( new Complex128( 1.0, 2.0 ) );
// returns 'complex128'
```
If provided an argument having an unknown or unsupported [data type][@stdlib/complex/dtypes], the function returns `null`.
```javascript
var dt = dtype( 'beep' );
// returns null
```
## Examples
```javascript
var dtypes = require( '@stdlib/complex/dtypes' );
var ctors = require( '@stdlib/complex/ctors' );
var dtype = require( '@stdlib/complex/dtype' );
// Get a list of supported complex number data types:
var DTYPES = dtypes();
// For each supported data type, create a complex number and confirm its data type...
var ctor;
var dt;
var i;
for ( i = 0; i < DTYPES.length; i++ ) {
ctor = ctors( DTYPES[ i ] );
dt = dtype( new ctor( 1.0, 2.0 ) );
console.log( '%s == %s => %s', DTYPES[ i ], dt, DTYPES[ i ] === dt );
}
```
[@stdlib/complex/dtypes]: https://github.com/stdlib-js/complex/tree/main/dtypes
[@stdlib/array/dtype]: https://www.npmjs.com/package/@stdlib/array-dtype