排序理解

sort排序时，List中存在两个相同元素，两个元素相同时，按照下标的先后顺序排序。

<script>
  var list = [
      {
          username:'758274',
          count:9,
          count2:8,
          time:30,
          time2:30,
      },
      {
          username:'758275',
          count:5,
          count2:10,
          time:30,
          time2:30,
      }
  ];
  list = list.sort(function(a,b){
      return (b.count * b.time + b.count2* b.time2) /(b.count+b.count2) - (a.count * a.time + a.count2* a.time2) /(a.count+a.count2)
  });
  console.log(list);
</script>