title: Get async data with Angular resolver
body: <p>I have resolver in my Angular 8 app</p>
  
  <pre><code>export class UserResolver implements Resolve&lt;any&gt; {
  
    constructor(
      private authService: AuthService,
    ) { }
  
    resolve() {
      this.authService.user.subscribe(user =&gt; {
        return user
      })
    }
  }
  </code></pre>
  
  <p>But this is assign <code>null</code> to a router data, because <code>user</code> came with async function in my service (it came from the Subject). How can I make resolver to wait for data from my service to be returned, and not assign null value to a data?</p>