pseudo-ish code change queue

queue.js

const saveQueue = [
  slide,
  slide1,
  slide2,
  slide
];

const attemptedSlides = {};
const running = false;

addToQueue (slide) {
  saveQueue.push(slide);

  if (!running) {
    processQueue();
  }
}

processQueue() {
  const itemToSave = saveQueue.shift();

  if (typeof itemToSave !== 'undefined') {
    running = true;
    
    if (attemptedSlides[itemToSave.id]){
      attemptedSlides[itemToSave.id] ++;
    } else {
      attemptedSlides[itemToSave.id] = 1;
    }

    saveFunction(itemToSave).then(() => {
      attemptedSlides[itemToSave.id] = undefined;
      setTimeout(processQueue, 0); // setTimeout to release the thread
    }, () => {
      if (attemptedSlides[itemToSave.id] < 3) {
        saveQueue.unshift(itemToSave);
        setTimeout(processQueue, 100); // wait 100 ms to see if things get better
      } else {
        setTimeout(processQueue, 0); // exceeded attempts... sorry man
      }
    });
  } else {
    running = false;
  }
}

I am also trying to decide between a deep clone when the item is added or just letting it be passed by reference. Pass by reference makes the dedupe easy because you just check to see if that thing is already enqueued and then bail on adding it if it is. Where as the deep clone would allow you to do gradual updates of the object.

I am leaning towards no deep clone... seems a little more elegant to me.