javascript转时间格式

var timestamp = 1617223881; // 时间戳

var date = new Date(timestamp * 1000); // 时间戳转日期，注意要乘以1000

console.log(date.getFullYear() + '-' + (date.getMonth() + 1) + '-' + date.getDate() + ' ' + date.getHours() + ':' + date.getMinutes() + ':' + date.getSeconds());

var date = new Date('2021-04-01 12:34:56');

var timestamp = date.getTime() / 1000;

console.log(timestamp);

var date = new Date('2021-04-01 12:34:56');

function fORMat(date, fmt) {
  var o = {
    'M+': date.getMonth() + 1,
    'd+': date.getDate(),
    'H+': date.getHours(),
    'm+': date.getMinutes(),
    's+': date.getSeconds(),
    'q+': Math.floor((date.getMonth() + 3) / 3),
    'S': date.getMilliseconds()
  };

  if (/(y+)/.test(fmt)) {
    fmt = fmt.replace(RegExp.$1, (date.getFullYear() + '').substr(4 - RegExp.$1.length));
  }

  for (var k in o) {
    if (new RegExp('(' + k + ')').test(fmt)) {
      fmt = fmt.replace(RegExp.$1, (RegExp.$1.length === 1) ? (o[k]) : (('00' + o[k]).substr(('' + o[k]).length)));
    }
  }

  return fmt;
}

console.log(format(date, 'yyyy-MM-dd HH:mm:ss'));