JS代码片段：一个日期离现在多久了

var dateDiff = function(hisTime,nowTime){
    if(!arguments.length) return '';
    var arg = arguments,
            now =arg[1]?arg[1]:new Date().getTime(),
            diffValue = now - arg[0].getTime(),
            result={
                isToday:false
            },
            minute = 1000 * 60,
            hour = minute * 60,
            day = hour * 24,
            halfamonth = day * 15,
            month = day * 30,
            year = month * 12,

            _year = diffValue/year,
            _month =diffValue/month,
            _week =diffValue/(7*day),
            _day =diffValue/day,
            _hour =diffValue/hour,
            _min =diffValue/minute;

    if(new Date().toDateString()==hisTime.toDateString()){
        result.isToday=true;
    }
    if(_year>=1) result.text=parseInt(_year) + "年前";
    else if(_month>=1) result.text=parseInt(_month) + "个月前";
    else if(_week>=1) result.text=parseInt(_week) + "周前";
    else if(_day>=1) result.text=parseInt(_day) +"天前";
    else if(_hour>=1) result.text=parseInt(_hour) +"个小时前";
    else if(_min>=1) result.text=parseInt(_min) +"分钟前";
    else result.text="刚刚";
    return result;
}

  //此方法来源于 https://github.com/vuejs/vue-hackernews/blob/gh-pages/src/filters/index.js
  function fromNow (dateStr) {
      const between = Date.now() / 1000 - Number(new Date(dateStr.replace(/-/g,'/')).getTime()) / 1000;
      if (between < 3600) {
          return (~~(between / 60)+'分钟前');
      } else if (between < 86400) {
          return (~~(between / 3600)+'小时前');
      } else {
          return (~~(between / 86400)+'天前');
      }
  }

  function isToday(dateStr){
      return (new Date().toDateString()==(new Date(dateStr.replace(/-/g,'/')).toDateString()));
  }