Nestjs using axios

Question

This simple demo has an error https://docs.nestjs.com/techniques/http-module

import { Get, Controller, HttpService } from '@nestjs/common';
import { AxiosResponse } from 'axios'
import { Observable } from 'rxjs'
@Controller()
export class AppController {
  constructor(private readonly http: HttpService) {}
  @Get()
  root(): Observable<AxiosResponse<any>>  {
    return this.http.get('https://api.github.com/users/januwA');
  }
}

What should I do?

[Nest] 7356   - 2018-10-18 00:08:59   [ExceptionsHandler] Converting circular structure to JSON +9852ms
TypeError: Converting circular structure to JSON
    at JSON.stringify (<anonymous>)

---

nest i
common version : 5.1.0
core version   : 5.1.0

Answer 1

You cannot just return the whole AxiosResponse object because it cannot be serialized to JSON. You most likely want to get the response data like this:

@Get()
root() {
  return this.http.get('https://api.github.com/users/januwA').pipe(
    map(response => response.data)
  );
}

---

or alternatively using Promises:

@Get()
async root() {
  const response = await this.http.get('https://api.github.com/users/januwA').toPromise();
  return response.data;
}

Answer 2

as you write in your example, get method return AxiosResponse<> and contains circular reference. So if you want to proxify webservice https://api.github.com/users/januwA, you should return AxiosResponse.data :

import { Get, Controller, HttpService } from '@nestjs/common';
import { AxiosResponse } from 'axios'
import { Observable } from 'rxjs'
@Controller()
export class AppController {
  constructor(private readonly http: HttpService) {}
  @Get()
  root(): Observable<any>{
    return this.httpClient.get('https://api.github.com/users/quen2404')
      .pipe(map(response => response.data));
  }
}

Answer 3

You have to make sure to handle your responses as a JSON you can return it as a promise and get the data, use one of both or HttpService or axios

import { Get, Controller, HttpService } from '@nestjs/common';
@Controller()
export class AppController {
  constructor(private readonly http: HttpService) {}
  @Get()
      root(): {
        return this.http.get('https://api.github.com/users/quen2404')
        .toPromise()
        .then(res => res.data)
        .catch(err => /*handle error*/)
      }
}