数组排序问题

我有如下数组，我已经按每个item的index递减排序了，现在的需求是如果index相等的情况下，按time递增排序该如何处理呢？

[{
        "gname": "gname661",
        "index": 9,
        "time": "2016-07-26 01:54:21"
      },
      {
        "gname": "gname600",
        "index": 9,
        "time": "2016-07-04 14:30:54"
      },
      {
        "gname": "gname559",
        "index": 8,
        "time": "2016-07-22 17:16:32"
      },
      {
        "gname": "gname508",
        "index": 8,
        "time": "2016-07-10 01:31:28"
      },
      {
        "gname": "gname402",
        "index": 7,
        "time": "2016-07-12 17:34:41"
      }]