Firebase event "<user> is writing..." like WhatsApp

Is there any manner to clone the whatsapp event "[user] is writing..." in Firebase events?

I have reading about the Firebase events in https://www.firebase.com/docs/web/api/ but I've not found anything about the issue.

Thanks.

I wrote such a typing indicator a while ago.

var ref = new Firebase('https://<your-app>.firebaseio.com');
var input = document.getElementById('input');
var typers = document.getElementById('typers');
var uid = Date.now(); // generate a fake user id
var timer;

// attach a listener that display all people current typing in a list
ref.on('value', function(snapshot) {
  typers.innerText = '';
  snapshot.forEach(function(typer) {
    var li = document.createElement('li');
    li.innerText = typer.key();
    typers.appendChild(li);
  });
});

// whenever the content of the textarea changes
input.addEventListener('input',function(e) {
  // mark this user a "typing"
  ref.child(uid).set(true);
  // if we're counting down, stop the timer
  if (timer) clearTimeout(timer);
  // remove this user in 2 seconds
  timer = setTimeout(function() {
    ref.child(uid).remove();
  }, 2000);
});

To see it in action, have a look at this JSBin. The tweet where I announced it.