code: function(arr) {
    arr = arr.sort((a, b) => {
      if (a.index > b.index) {
        return 1;
      }
      if (a.index === b.index) {
        return 0;
      }
      return -1;
    });
    //return ts objects
    return arr.map((o) => o.ts);
  }
docs: perform sort on pre-computed values