Is this recursion or not

Question

function x(){
  window.setTimeout(function(){
     foo();
     if(notDone()){ 
        x();
     };
  },1000);
}

My concern being unbounded stack g

Answer 1

Recursion has many different definitions, but if we define it as the willful (as opposed to bug-induced) use of a function that calls itself repeatedly in order to solve a programming problem (which seems to be a common one in a Javascript context), it absolutely is.

The real question is whether or not this could crash the browser. The answer is no in my experience...at least not on Firefox or Chrome. Whether good practice or not, what you've got there is a pretty common Javascript pattern, used in a lot of semi-real-time web applications. Notably, Twitter used to do something very similar to provide users with semi-real-time feed updates (I doubt they still do it now that they're using a Node server).

Also, out of curiously I ran your script with the schedule reset to run every 50ms, and have experienced no slowdowns.