angular get response headers

this.authenticationService.login(this.f.email.value, this.f.password.value)
  .pipe(first())
  .subscribe(
    (data: HttpResponse<any>) => {
      console.log(data.headers.get('authorization'));
    },
    error => {
      this.loading = false;
    });

At my Service Side.

return this.http.post<any>(Constants.BASE_URL + 'login', {username: username, password: password},
  {observe: 'response' as 'body'})
  .pipe(map(user => {
       return user;
  }));

http
  .get<MyJsonData>('/data.json', {observe: 'response'})
  .subscribe(resp => {
    // Here, resp is of type HttpResponse<MyJsonData>.
    // You can inspect its headers:
    console.log(resp.headers.get('X-Custom-Header'));
    // And access the body directly, which is typed as MyJsonData as requested.
    console.log(resp.body.someField);
  });