src/Controller/BaseController.php
public function sendErrorResponse($message, $code, $httpStatusCode, $data = null)
    {

        \Yii::$app->response->format = Response::FORMAT_JSON;
        \Yii::$app->response->setStatusCode($httpStatusCode, $this->httpStatuses->getReasonPhrase($httpStatusCode));

        $response = [
            'status' => 'error',
            'message' => $message,
            'code' => $code
        ];

        if (!is_null($data)) {
            $response["data"] = $data;
        }

        return $response;
    }
public function sendErrorResponse($message, $code, $httpStatusCode, $data = null)
    {

        \Yii::$app->response->format = Response::FORMAT_JSON;
        \Yii::$app->response->setStatusCode($httpStatusCode, $this->httpStatuses->getReasonPhrase($httpStatusCode));

        $response = [
            'status' => 'error',
            'message' => $message,
            'code' => $code
        ];

        if (!is_null($data)) {
            $response["data"] = $data;
        }

        return $response;
    }
Allows sending error response
@author Oluwarotimi Akintewe <akintewe.rotimi@gmail.com>
@author Adegoke Obasa <goke@cottacush.com>
@param $message
@param $code
@param $httpStatusCode
@param null $data
@return array