计算输入的时间是当前时间的一分钟前，一小时前，一天前

javascript方法：

function timeago(dateTimeStamp){   //dateTimeStamp是一个时间毫秒，注意时间戳是秒的形式，在这个毫秒的基础上除以1000，就是十位数的时间戳。13位数的都是时间毫秒。
    var minute = 1000 * 60;      //把分，时，天，周，半个月，一个月用毫秒表示
    var hour = minute * 60;
    var day = hour * 24;
    var week = day * 7;
    var halfamonth = day * 15;
    var month = day * 30;
    var now = new Date().getTime();   //获取当前时间毫秒
    console.log(now)
    var diffValue = now - dateTimeStamp;//时间差

    if(diffValue < 0){
        return;
    }
    var minC = diffValue/minute;  //计算时间差的分，时，天，周，月
    var hourC = diffValue/hour;
    var dayC = diffValue/day;
    var weekC = diffValue/week;
    var monthC = diffValue/month;
    if(monthC >= 1 && monthC <= 3){
        result = " " + parseInt(monthC) + "月前"
    }else if(weekC >= 1 && weekC <= 3){
        result = " " + parseInt(weekC) + "周前"
    }else if(dayC >= 1 && dayC <= 6){
        result = " " + parseInt(dayC) + "天前"
    }else if(hourC >= 1 && hourC <= 23){
        result = " " + parseInt(hourC) + "小时前"
    }else if(minC >= 1 && minC <= 59){
        result =" " + parseInt(minC) + "分钟前"
    }else if(diffValue >= 0 && diffValue <= minute){
        result = "刚刚"
    }else {
        var datetime = new Date();
        datetime.setTime(dateTimeStamp);
        var Nyear = datetime.getFullYear();
        var Nmonth = datetime.getMonth() + 1 < 10 ? "0" + (datetime.getMonth() + 1) : datetime.getMonth() + 1;
        var Ndate = datetime.getDate() < 10 ? "0" + datetime.getDate() : datetime.getDate();
        var Nhour = datetime.getHours() < 10 ? "0" + datetime.getHours() : datetime.getHours();
        var Nminute = datetime.getMinutes() < 10 ? "0" + datetime.getMinutes() : datetime.getMinutes();
        var Nsecond = datetime.getSeconds() < 10 ? "0" + datetime.getSeconds() : datetime.getSeconds();
        result = Nyear + "-" + Nmonth + "-" + Ndate
    }
    return result;
}

friendly.js 计算指定时间到当前时间的时间差
该方法是vux的 filter中的一个：

export default function (time) {
  let date = (typeof time === 'number') ? new Date(time) : new Date((time || '').replace(/-/g, '/'))
  let diff = (((new Date()).getTime() - date.getTime()) / 1000)
  let dayDiff = Math.floor(diff / 86400)

  let isValidDate = Object.prototype.toString.call(date) === '[object Date]' && !isNaN(date.getTime())

  if (!isValidDate) {
    console.error('not a valid date')
  }
  const formatDate = function (date) {
    let today = new Date(date)
    let year = today.getFullYear()
    let month = ('0' + (today.getMonth() + 1)).slice(-2)
    let day = ('0' + today.getDate()).slice(-2)
    let hour = today.getHours()
    let minute = today.getMinutes()
    let second = today.getSeconds()
    return `${year}-${month}-${day} ${hour}:${minute}:${second}`
  }

  if (isNaN(dayDiff) || dayDiff < 0 || dayDiff >= 31) {
    return formatDate(date)
  }

  return dayDiff === 0 && (
      diff < 60 && '刚刚' ||
      diff < 120 && '1分钟前' ||
      diff < 3600 && Math.floor(diff / 60) + '分钟前' ||
      diff < 7200 && '1小时前' ||
      diff < 86400 && Math.floor(diff / 3600) + '小时前') ||
    dayDiff === 1 && '昨天' ||
    dayDiff < 7 && dayDiff + '天前' ||
    dayDiff < 31 && Math.ceil(dayDiff / 7) + '周前'
}

参考：
https://blog.youkuaiyun.com/bule_chen/article/details/79219381
https://blog.youkuaiyun.com/qq_32921327/article/details/78564576