title: How can i know what field of firebase was changed (using listener)?
body: <p>I have the follow listener on my application:</p>
  <pre><code>firebase.database().ref(&quot;salas/&quot; + id).on(&quot;value&quot;, snapshot =&gt; {
     do something...
  })
  </code></pre>
  <p>and the follow structure on firebase:</p>
  <p><img src="https://i.stack.imgur.com/ti7EL.png" alt="Firebase structure image" /></p>
  <p>So, i need to know what field was changed. If any field or node of this structure is changed, the .on() method is called and i can get the all updated node, but, i need to do what node or key was changed,  what was the trigger for the call of method .on(), example, if was key &quot;tela&quot; or node &quot;acomp_jogo&quot;. Is it possible?</p>