title: Firestore getting Javascript Date instead of Timestamp
body: <p>I'm using <code>Angular 6</code> and <code>Firestore</code> to develop an application where I'm saving my dates as Javascript's <code>Date</code> object. The issue is that when I do <code>snapshotChanges()</code>, It returns a <code>Unix Timestamp</code> instead of the Date object that is in my database.</p>
  
  <p>I searched the solutions online (<a href="https://github.com/firebase/firebase-js-sdk/issues/726#issuecomment-385163921" rel="nofollow noreferrer">this</a>, <a href="https://github.com/angular/angularfire2/issues/1575#issuecomment-385092252" rel="nofollow noreferrer">and this</a>) and found this <strong>config option</strong> for Firestore: </p>
  
  <p><code>{ timestampsInSnapshots: false }</code></p>
  
  <p>I'm trying to apply this in my app component like this:</p>
  
  <pre><code>constructor(private _db: AngularFirestore) {
      _db.firestore.settings({ timestampsInSnapshots: false });
    }
  </code></pre>
  
  <p>But then I get this <strong>error</strong>:</p>
  
  <p><code>Firestore has already been started and its settings can no longer be changed. You can only call settings() before calling any other methods on a Firestore object.</code></p>
  
  <p>I've also tried to change the settings before calling <code>snapshotChanges()</code> but, that also does not have any effect on the behaviour.</p>
  
  <p>Note: I'm also using <code>AngularFirestoreModule.enablePersistence()</code></p>
  
  <p><strong>Update:</strong></p>
  
  <p>I tried <a href="https://github.com/angular/angularfire2/issues/1575#issuecomment-388491790" rel="nofollow noreferrer">this</a> and it gives me this error:</p>
  
  <p><code>@firebase/firestore: Firestore (5.0.3): 
  The behavior for Date objects stored in Firestore is going to change
  AND YOUR APP MAY BREAK.</code></p>
  
  <p>Any suggestions would be great.</p>