How to limit (or queue) calls to external processes in Node.JS?

Question

Scenario

I have a Node.JS service (written using ExpressJS) that accepts image uploads via DnD (example). After an image is uploaded, I do a few thi

Answer 1

For anyone who thought Brandon's quick-and-dirty might be too quick-and-dirty, here's a variation that is no longer and doesn't have the unnecessary busy-wait. I'm not in a position to test it but it should work.

var enqueue = function() {
  var queue = [];
  var execImmediate = function(fImmediate) {
    enqueue = function(fDelayed) 
      queue.push(fDelayed);
    };
    fImmediate();

    var ic = setInterval(function() {
      var fQueued = queue.shift();
      if (fQueued) {
        fQueued();
      } else {
        clearInterval(ic);
        enqueue = execImmediate;
      }
    }, 1000);
  };
  return execImmediate;
}();