js时间格式转换

function getDateTimeStamp(dateStr){
  console.log(dateStr.replace(/-/gi,"/"))
  return Date.parse(dateStr.replace(/-/gi,"/"));
}
getDateTimeStamp('2020/04/14 20:00')
---打印出 1586865600000
getDateTimeStamp('2020-04-14 20:00')
---打印出 1586865600000

let d = new Date('2020-04-14 20:00')
let t = d.getTime(d) // 方法1
let t = d.valueOf(d) // 方法2
let t = d.parse(d) // 方法3
console.log(t);
---打印出 1586865600000

const format = (time, format = 'yyyy-mm-dd') => {
  const d = time ? new Date(time) : new Date();
  const t = (i) =>; { return (i < 10 ? '0' : '') + i };
  const year = d.getFullYear();
  const month = d.getMonth() + 1;
  const day = d.getDate();
  const hour = d.getHours();
  const minutes = d.getMinutes();
  const seconds = d.getSeconds();
  const weekday = d.getDay();
  return format.replace(/(yy){1,2}|m{1,2}|d{1,2}|h{1,2}|i{1,2}|s{1,2}|w{1,2}/gi, function(r) {
    switch (r.toUpperCase()) {
      case 'YY':
        return ('' + year).substr(2);
      case 'YYYY':
        return year;
      case 'M':
        return month;
      case 'MM':
        return t(month);
      case 'D':
        return day;
      case 'DD':
        return t(day);
      case 'H':
        return hour;
      case 'HH':
        return t(hour);
      case 'I':
        return minutes;
      case 'II':
        return t(minutes);
      case 'S':
        return seconds;
      case 'SS':
        return t(seconds);
      case 'W':
        return `星期${['日', '一', '二', '三', '四', '五', '六'][weekday]}`;
      case 'WW':
        return ['Sunday', 'Monday', 'TuesDay', 'Wednesday', 'Thursday', 'Friday', 'Saturday'][weekday];
    }
  });
}
format(1586865600000); // 2020-04-14
format(1586865600000, 'yyyy/mm/dd hh:ii:ss'); // 2020/04/14 20:00:00
format(1586865600000, 'yy/m/d hh:ii:ss'); // 20/4/14 20:00:00
format(1586865600000, 'yyyy/mm/dd w'); // 2020/04/14 星期二
format(1586865600000, 'mm/dd/yyyy'); // 04/14/2020

getDateTimeStamp('2020-04-14 20:00:00')--将时间转化为时间戳
function getDateTimeStamp(dateStr){
console.log(dateStr.replace(/-/gi,"/"))
let dateTimeStamp = dateStr.replace(/-/gi,"/");
getDateDiff(dateTimeStamp)
 return Date.parse(dateStr.replace(/-/gi,"/"));
}
function getDateDiff(dateTimeStamp){--将时间戳和当前时间比较，转化为特定的形式
  var minute = 1000 * 60;
  var hour = minute * 60;
  var day = hour * 24;
  var halfamonth = day * 15;
  var month = day * 30;
  var now = new Date().getTime();
  var diffValue = now - dateTimeStamp;
  if(diffValue < 0){return;}
  var monthC =diffValue/month;
  var weekC =diffValue/(7*day);
  var dayC =diffValue/day;
  var hourC =diffValue/hour;
  var minC =diffValue/minute;
  if(monthC>=1){
    result="" + parseInt(monthC) + "月前";
  }
  else if(weekC>=1){
    result="" + parseInt(weekC) + "周前";
  }
  else if(dayC>=1){
    result=""+ parseInt(dayC) +"天前";
  }
  else if(hourC>=1){
    result=""+ parseInt(hourC) +"小时前";
  }
  else if(minC>=1){
    result=""+ parseInt(minC) +"分钟前";
  }else
  result="刚刚";
  return result;
}