时间戳格式化转换为日期格式

1、dayjs ：github.com/iamkun/dayj…
2、
<!doctype html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title></title>
</head>

<body>
  <script type="text/javascript">
    Date.prototype.Format = function (fmt) {
      var o = {
        "M+": this.getMonth() + 1, //月份
        "d+": this.getDate(), //日
        "h+": this.getHours(), //小时
        "m+": this.getMinutes(), //分
        "s+": this.getSeconds(), //秒
        "q+": Math.floor((this.getMonth() + 3) / 3), //季度
        "S": this.getMilliseconds() //毫秒
      };
      if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
      for (var k in o)
        if (new RegExp("(" + k + ")").test(fmt)) fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
      return fmt;
    }
    function timestamp_to_datetime(ts, type) {
      var time = '';
      var length = (ts+'').length;
      if (length === 10) {
        time = ts * 1000;
      } else {
        time = ts;
      }
      var date = new Date(time);
      return date.Format(type)
    }
    var date_str = timestamp_to_datetime(1564987319000, 'yyyy/MM/dd hh:mm:ss'); // 2019/08/05 14:41:59
    // var date_str = timestamp_to_datetime(1512622621, 'yyyy/MM/dd'); //2017/12/07
    console.log(date_str);
  </script>
</body>

</html>