如何判断两个日期是不是同一天？

/**
 * 判断是否是同一天
 */
 isSameDay(date1: number | string | Date, date2: number | string | Date) {
  date1 = this.getFormatDate(date1);
  date2 = this.getFormatDate(date2);
  let blSameYear = date1.getFullYear() == date2.getFullYear();
  let blSameMonth = date1.getMonth() == date2.getMonth();
  let blSameDay = date1.getDate() == date2.getDate();
  return blSameYear && blSameMonth && blSameDay;
}
getFormatDate(date: number | string | Date | undefined): Date {
  if (date == undefined || date == null) { //无参数
    date = new Date();
  } else if (typeof (date) == "string") { //字符串日期
    if (date.length == 0) {
      date = new Date();
    } else {
      let dateStr = date.replaceAll("-", '/')
        .replace("年", '/')
        .replace("月", '/')
        .replace("日", ' ')
        .replace("  ", ' ')
        .replace("时", ':')
        .replace("分", ':')
        .replace("秒", '')
      date = new Date(dateStr);
    }
  } else if (typeof (date) == "number") { //时间戳
    date = new Date(date);
  } else {
    date = new Date(date);
  }
  return date;
}