title: How do I sign out users in Firebase 3.0?
body: <p>According to <a href="https://firebase.google.com/docs/reference/js/firebase.auth.Auth" rel="noreferrer">documentation</a>, I force a user to sign out with the method <code>signOut()</code>.</p>
  
  <p>This is what I have tried:</p>
  
  <pre><code>var rootRef = firebase.database().ref();
  var loggedInUser = firebase.auth();
  
  1. firebase.signOut(); 
  2. loggedInUser.signOut(); 
  3. rootRef.signOut();
  4. signOut();
  5. firebase.auth.signOut();
  </code></pre>
  
  <p>I get <code>... is not a function</code> for every one of the five above. I know there is no issue with my reference to the new Firebase, since <code>firebase.database().ref();</code> and <code>firebase.auth();</code> does not throw error. I have also migrated the app in the console.</p>