function sleepSort(arr) {
  var output = [];
  for (var i = 0; i < arr.length; i++) {
    setTimeout(output.push.bind(output, arr[i]), arr[i] * 100);
  }
  return output;
}

function populateArray(n) {
  var arr = [];
  for (var i = 0; i < n; i++) {
    arr.push(Math.floor(Math.random() * 100));
  }
  return arr;
}

var arr = populateArray(100);
console.log('initial array', arr);

var sorted = sleepSort(arr);
var interval = setInterval(function() {
  console.log('sorting array', sorted);
  if (sorted.length === arr.length) {
    clearInterval(interval);
    console.log('done sorting!', sorted);
  }
}, 100);