title: firebase get recently added snapshot value (only one)
body: <p>How to retrieve only one recently added child value from firebase without timestamp comparision?</p>
  
  <p>I want to get the same key/value (only one child, not full array of child nodes) on the client side while adding it through my firebase console.</p>
  
  <pre><code>{users:
     "id-ue3": "bob",
     "id-om4": "john", // &lt;-- recently added
     "id-ker": "kevin" 
  }
  
  firebase.database().ref().on('child_changed', function(snapshot) {
     ....
     console.log(last_name); // output --&gt; "john"
  });
  </code></pre>