How to change setTimeout number?

Question

lets say a website receives some data from users continuously. I want it to alert() users if it haven't received data from users in as long as 5 seconds.
this is How I'm trying to do it:

countDown = 5000

if(//some data received from user){
  countDown = 5000
}

setTimeout(
    function() {
        alert('no data in 5 seconds')
    }, countDown);
}

well it's not working because It can't set countDown to 5 sec every time It receives data from users, So How can I do this?

and since the data from user comes continuously I guess it wouldn't be good for performance to run a new setTimeout() and destroy the old one every time.(?)

Answer 1

This would be more of a recursive function that checks if there is any data. If not, it makes a function that runs in five seconds. If the data is still not there, you repeat the process.

let countDown = 5000

function someFunction() {
  //this is called when you recieve data 
  timeoutFunc();
}

function timeoutFunc() {
  setTimeout(
    function() {
      if (//still don't have new data) {
        alert('no data in 5 seconds');
        timeoutFunc();
      }
    }, countDown);
  } 
}