js格式化时间戳

//datetime是拿到的时间戳
var date = new Date(datetime);//时间戳为10位需*1000，时间戳为13位的话不需乘1000 
var year = date.getFullYear(),
    month = ("0" + (date.getMonth() + 1)).slice(-2),
    sdate = ("0" + date.getDate()).slice(-2),
    hour = ("0" + date.getHours()).slice(-2),
    minute = ("0" + date.getMinutes()).slice(-2),
    second = ("0" + date.getSeconds()).slice(-2);
// 拼接
var result = year + "-"+ month +"-"+ sdate +" "+ hour +":"+ minute +":" + second;
// 返回
return result;