NestJS returning the result of an HTTP request

This issue comes from the axios library. In order to fix that, you have to pull out the data property:

return this.httpService.post(...)
  .pipe(
    map(response => response.data),
  );

The problem seems to stem from the fact that we are trying to return a Response object directly, and that is circular by nature. I'm not sure of the correct way to implement this, but I was able to get around it by using axios directly, unwrapping the promise and returning just the data.

@Post('login')
  async authenticateUser(@Body() LoginDto) {
    const params = JSON.stringify(LoginDto);

    return await axios.post('https://api.example.com/authenticate_user',
      params,
      {
        headers: {
          'Content-Type': 'application/json',
        },
      }).then((res) => {
          return res.data;
    });
}

UPDATE

I realized I could just do the same thing to the Observable being returned from the httpService using the new rxjs pipe method, so that's probably the better way to do it.

@Post('login')
async authenticateUser(@Body() LoginDto) {
    const params = JSON.stringify(LoginDto);

    return this.httpService.post('https://api.example.com/authenticate_user',
      params,
      {
        headers: {
          'Content-Type': 'application/json',
        },
      }).pipe(map((res) => {
    return res.data;
  }));
}