Firebase活动“<用户>正在写...“像WhatsApp [英] Firebase event "<user> is writing..." like WhatsApp

问题描述

是否有任何方式在Firebase事件中克隆whatsapp事件 [user]正在撰写... ？

阅读 https://www.firebase.com/docs/web/api/上的Firebase活动但是我还没有发现任何问题。
$ b $ p

谢谢。

解决方案

  var ref = new Firebase（'https： //<your-app>.firebaseio.com'）; 
 var input = document.getElementById（'input'）; 
 var typers = document.getElementById（'typers'）; 
 var uid = Date.now（）; //产生一个假的用户ID 
 var timer; 
 
 //附加一个侦听器，显示当前在列表中输入的所有人员
 ref.on（'value'，function（snapshot）{
 typers.innerText =''; 
 snapshot.forEach（function（typer）{
 var li = document.createElement（'li'）; 
 li.innerText = typer.key（）; 
 typers.appendChild （li）; 
}）; 
}）; 
 
 //每当textarea的内容改变时
 input.addEventListener（'input'，function（e）{
 //标记这个用户一个输入
 ref.child（uid）.set（true）; 
 //如果我们倒计时，停止定时器
 if（timer）clearTimeout（timer）; 
 //删除用户在2秒内
 timer = setTimeout（function（）{
 ref.child（uid）.remove（）; 
}，2000）; 
}）; 
  

若要查看它，请查看这个JSBin 。
我宣布的 tweet 。

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.

解决方案

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.

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