Encapsulation implementation of the data format returned by nestjs to the front end

{
  "id": 1,
  "uuid": "cbbe7abc-b95e-48a0-8d24-b1ac93c45328",
  "name": "Husky 1",
  "age": 12,
  "color": null,
  "createAt": "2019-07-25T09:13:30.000Z",
  "updateAt": "2019-07-25T09:13:30.000Z"
}

{
 code: 0,
 message: "Request successful",
 data: {
  "id": 1,
  "uuid": "cbbe7abc-b95e-48a0-8d24-b1ac93c45328",
  "name": "Husky 1",
  "age": 12,
  "color": null,
  "createAt": "2019-07-25T09:13:30.000Z",
  "updateAt": "2019-07-25T09:13:30.000Z"
 }
}

nest gf filters/httpException

import {
 ArgumentsHost,
 Catch,
 ExceptionFilter,
 HttpException,
 HttpStatus,
 Logger,
} from '@nestjs/common';

@Catch(HttpException)
export class HttpExceptionFilter implements ExceptionFilter {
 catch(exception: HttpException, host: ArgumentsHost) {
  const ctx = host.switchToHttp();
  const response = ctx.getResponse();
  const request = ctx.getRequest();

  const message = exception.message.message;
  Logger.log('error prompt', message);
  const errorResponse = {
   data: {
    error: message,
   }, // Get all error messages message: 'Request failed',
   code: 1, // custom code
   url: request.originalUrl, // wrong url address};
  const status =
   exception instanceof HttpException
    ? exception.getStatus()
    : HttpStatus.INTERNAL_SERVER_ERROR;
  // Set the returned status code, request header, and send error information response.status(status);
  response.header('Content-Type', 'application/json; charset=utf-8');
  response.send(errorResponse);
 }
}

...
import { HttpExceptionFilter } from './filters/http-exception.filter';

async function bootstrap() {
 ...
 // Globally register error filters app.useGlobalFilters(new HttpExceptionFilter());
}
bootstrap();

{
 "statusCode": 400,
 "error": "Bad Request",
 "data": {
  "message": [
   {
    "age": "Required integer"
   }
  ]
 },
 "message": 'Request failed',
 "code": 1,
 "url": "/api/v1/cat"
}

import {
 Injectable,
 NestInterceptor,
 CallHandler,
 ExecutionContext,
} from '@nestjs/common';
import { map } from 'rxjs/operators';
import { Observable } from 'rxjs';
interface Response<T> {
 data: T;
}
@Injectable()
export class TransformInterceptor<T>
 implements NestInterceptor<T, Response<T>> {
 intercept(
  context: ExecutionContext,
  next: CallHandler<T>,
 ): Observable<Response<T>> {
  return next.handle().pipe(
   map(data => {
    return {
     data,
     code: 0,
     message: 'Request successful',
    };
   }),
  );
 }
}

...
import { TransformInterceptor } from './interceptor/transform.interceptor';

async function bootstrap() {
 ...
 // Globally registered interceptor app.useGlobalInterceptors(new TransformInterceptor());
 ...
}
bootstrap();

{
 "data": {
  "id": 1,
  "uuid": "cbbe7abc-b95e-48a0-8d24-b1ac93c45328",
  "name": "Husky 1",
  "age": 12,
  "color": null,
  "createAt": "2019-07-25T09:13:30.000Z",
  "updateAt": "2019-07-25T09:13:30.000Z"
 },
 "code": 0,
 "message": "Request successful"
}