code: function portChecker( server ) {
    return ( result ) => {
      detect( server.port ).then(( port ) => {
        if ( port === server.port ) {
          result( server );
        } else {
          print( chalk.yellow( `Something is already running on port ${server.port}.` ));
          print();
        }
      });
    };
  }
docs: check port