code: public function respondWithMessage( $message = null ) {
  
  		$res[ 'status' ] = $this->getStatusText();
  
  		//if it's about failure
  		if ( $this->getErrorCode() ) {
  
  			$res[ 'error' ] = $this->getErrorCode();
  
  			if ( is_null( $message ) )
  		     $res[ 'message' ] = $this->getErrorMessage();
  		    else
  		     $res[ 'message' ] = $message;
  
  		} else {
  
  			$res[ 'message' ] = $message;
  
  		}
  
  		return $this->respond( $res );
  
  	}
docs: Response which conteins just a message
  @param string $message
  @author Shima Payro <sh.payro@anetwork.ir>
  @since May 2, 2016 9:49:21 AM
  @return Main|\Illuminate\Http\JsonResponse
  @uses
  @see