JS将时间戳转化成年-月-日

getNowFormatDate(n) {
        if(n==''){
          n=new Date()
        }
        var date = new Date(n);
        var seperator1 = "-";
        var year = date.getFullYear();
        var month = date.getMonth() + 1;
        var strDate = date.getDate();
        if (month >= 1 && month <= 9) {
          month = "0" + month;
        }
        if (strDate >= 0 && strDate <= 9) {
          strDate = "0" + strDate;
        }
        var currentdate = year + seperator1 + month + seperator1 + strDate;
        return currentdate;
      }