function resolve( dtype ) {
	var t = ( typeof dtype );
	if ( t === 'string' ) {
		return ( str2enum( dtype ) === null ) ? null : dtype;
	}
	if ( t === 'number' ) {
		return enum2str( dtype );
	}
	return null;
}
Returns the data type string associated with a supported ndarray data type value.

@param {*} dtype - data type value
@returns {(string|null)} data type string or null

@example
var str2enum = require( '@stdlib/ndarray/base/dtype-str2enum' );

var v = resolve( str2enum( 'float64' ) );
// returns 'float64'