Question: Converting circular structure to JSON

[Asim Husanović]

Hi there,

I am very new to NestJS and something I did wrong. If you can help me I will be very thankful :)

Module:

import { Global, Module } from '@nestjs/common';
import KeycloakService from './keycloak.service';
import { HttpModule } from 'nestjs-http-promise';

@Global()
@Module({
  imports: [
    HttpModule.register({
      timeout: 10000,
      retries: 3,
      retryDelay: () => {
        return 500;
      },
      baseURL: 'https://my-local-domain.local',
      headers: {
        Accept: 'application/json',
        'Content-type': 'application/json',
      },
    }),
  ],
  providers: [LocalService],
  exports: [LocalService],
})
class LocalModule {}
export default LocalModule;

Service:

import { Injectable } from '@nestjs/common';
import { HttpService } from 'nestjs-http-promise';

@Injectable()
class LocalService {
  constructor(private httpService: HttpService) {}

  public async callSomeServer(): Promise<any> {
    return await this.httpService.get('/users');
  }
}

export default LocalService;

Controller:

import { Controller, Get } from '@nestjs/common';
import LocalService from './local.service';

@Controller()
export class LocalController {
  constructor(private readonly localService: LocalService) {}

  @Get('/user')
  public async userCall(): Promise<any> {
    const ret = await this.localService.callSomeServer();

    console.log(ret);

    return ret;
  }
}

In the console, I get a response from the console.log(ret) but after that I have an error:

ERROR [ExceptionsHandler] Converting circular structure to JSON
    --> starting at object with constructor 'ClientRequest'
    |     property 'socket' -> object with constructor 'TLSSocket'
    --- property '_httpMessage' closes the circle

[Asim Husanović]

I have found a solution (It was fast :) )

In controller return have to be:

return ret.data;

[benhason1]

Hi, the response of axios request contains complex data structure with circular dependency in it which cause the problem.
Instead of logging the whole response I think you may want to log only the response: console.log(ret.data).
Also you can check this library which can flat circular json response.