Nestjs fastify use NestInterceptor auto stringify

[zaohuayudie]

Bug Report

Nestjs+Fastify, the return value is a string, and the expectation is json

controller.ts
@TypedRoute.Get('config')
async test() {
    return { name: 'zaohua', img: ''}
}

When I use TransformInterceptor:

import {
  CallHandler,
  ExecutionContext,
  Injectable,
  NestInterceptor,
} from '@nestjs/common';
import { map, Observable } from 'rxjs';
import { FastifyReply } from 'fastify';

interface Response<T> {
  data: T;
}

@Injectable()
export class TransformInterceptor<T>
  implements NestInterceptor<T, Response<T>>
{
  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    const res = context.switchToHttp().getResponse<FastifyReply<any>>();
    res.header('Content-Type', 'application/json; charset=utf-8');
    return next.handle().pipe(
      map((data) => {
        return {
          data,
          code: 0,
          msg: '请求成功',
        };
      }),
    );
  }
}

GET or Post response data is string
{
  "data": "{\"name\":\"zaohua\",\"img\":\"\"}",
  "code": 0,
  "msg": "请求成功"
}

Summary

Write a short summary of the bug in here.

• SDK Version: 2.6.4
• Expected behavior: data is json, {"name": "zaohua", "img":""}
• Actual behavior: data is string, "{\"name\":\"zaohua\", \"img\":\"\"}"

the same question : https://stackoverflow.com/questions/76884219/disable-nestinterceptor-auto-stringify

[samchon]

@TypedRoute() ensures type safety and boosts up serialization through typia.json.assertStringify() funtion.

Therefore, it is not possible to change the response object through the global interceptor, and it is intended spec of the @TypedRoute(): the responded object type must be same with its DTO type. If you don't want that, you have to use original @Post() or @Get() function of nestjs.

[zaohuayudie]

@TypedRoute() ensures type safety and boosts up serialization through typia.json.assertStringify() funtion.

Therefore, it is not possible to change the response object through the global interceptor, and it is intended spec of the @TypedRoute(): the responded object type must be same with its DTO type. If you don't want that, you have to use original @Post() or @Get() function of nestjs.

Thanks!