Angular service wait for Observable in constructor

Question

I have an Angular 2 service with this constructor:

constructor(public fireAuth: AngularFireAuth)
{
    console.log('1');
    fireAuth.authState.subscribe(user =>
    {
        console.log('2');
        this.user = user;
    });
    console.log('3');
}

When it's instantiated, the log order is 1, 3 and 2, because the 2nd log is inside the Observable. I can't use it async/await because it's in the service constructor . Is there any way to make this call synchronous?

Answer 1

You need to use the complete callback;

console.log('1');
fireAuth.authState.subscribe(
  user => {
      console.log('2');
      this.user = user;
  },
  error => console.error(error),
  () => {
      console.log('3');
  });