title: How to display data from firebase database in Ionic 3?
body: <p>I want to display my database data into ionic view.
  here detail data in my database:</p>
  
  <pre><code>{firstName: "John", lastName: "Doe", username: "jhondoe"}
  </code></pre>
  
  <p>my code in page controller:</p>
  
  <pre><code>import { AngularFireDatabase,  FirebaseObjectObservable  } from 'angularfire2/database';
  
  profile : FirebaseObjectObservable&lt;Profile&gt;;
  
  
  this.afAuth.authState.subscribe(data =&gt; {
    if(data.email &amp;&amp; data.uid){   
      this.afDatabase.object(`profile/${data.uid}`).valueChanges().subscribe(profile =&gt; {   
        this.profile = profile;
        console.log(profile);
      });
  
  });
  </code></pre>
  
  <p>view page:</p>
  
  <pre><code>&lt;ion-content padding&gt;
  
    &lt;p&gt;Username: {{ profile?.username | async }}&lt;/p&gt;
    &lt;p&gt;First Name: {{ profile?.firstName  | async }}&lt;/p&gt;
    &lt;p&gt;Last Name: {{ profile?.LastName  | async }}&lt;/p&gt;
  
  &lt;/ion-content&gt;
  </code></pre>
  
  <p>but it not work, and display error:</p>
  
  <blockquote>
    <p>InvalidPipeArgument: 'John' for pipe 'AsyncPipe'</p>
  </blockquote>