JavaScript获取几天前(后)的日期

/**

* 获取当前日期几天前的日期

* n为整数

*/

getAgoDay(n) {
    let date = new Date()
    let seperator = "-"
    let newDate = new Date(date.getTime() - n * 24 * 60 * 60 * 1000)
    let year = newDate.getFullYear()
    let month = newDate.getMonth() + 1
    let day = newDate.getDate()
    return year.toString() + seperator + month.toString() + seperator + day.toString()
},

console.log(new Date());//Thu Jul 27 2023 11:45:07 GMT+0800 (中国标准时间)
console.log(getAgoDay(2));//2023-7-25 

/**

* 获取日期格式yy-mm-dd hh:mm:ss

* time可为字符串日期，可为时间戳

*/

getFormaterDate(time){
   let date = time ? time : new Date()
   let year = date.getFullYear()//年
   let month = date.getMonth() + 1//月
   let day = date.getDate()//日
   let hour = date.getHours()//时
   let minute = date.getMinutes()//分
   let second = date.getSeconds()//秒
   if(month < 10) month = '0' + month
   if(hour < 10) hour = '0' + hour
   if(minute < 10) minute = '0' + minute
   if(second<10) second = '0' + second
   return year + '-' + month + '-' + day + ' ' + hour + ':' + minute + ':' + second
}

/**

* 获取几年前或几年后的日期

* n默认为0，大于零为n年后，小于零为n年前

*/

getAgoYears(n=0) {
   let date = new Date()
   let year = date.getFullYear()
   let month = date.getMonth() + 1
   let day = date.getDate()
   let hour = date.getHours()//时
   let minute = date.getMinutes()//分
   let second = date.getSeconds()//秒
   if(month < 10) month = '0' + month
   if(hour < 10) hour = '0' + hour
   if(minute < 10) minute = '0' + minute
   if(second<10) second = '0' + second
   return year + '-' + month + '-' + day + ' ' + hour + ':' + minute + ':' + second
}