Writing a Non-Blocking JavaScript Quicksort(breck-mckye.com)

  var code = "onmessage = function (evt) {evt.data.sort(); postMessage(evt.data)}";

  function asyncSort(data, cb) {
    var worker = new Worker(URL.createObjectURL(new Blob([code])));
    worker.onmessage = function (evt) { cb(evt.data); };
    worker.postMessage(data);
  }

  asyncSort([3, 2, 1], function (res) { console.log(res); });

  "[1, 2, 3]"

    function quicksort(arr, cb) {
        var thread_balance = 1;
        function thread(start, end) {
            if (not trivially solved) {
                partition_stuff;
                thread_balance += 1;
                setImmediate(...);
                setImmediate(...);
            } else {
                thread_balance -= 1; // this thread is done.
                if (thread_balance === 0) {
                    cb(arr);
                }
            }
        }
        thread(0, arr.length);
    }