Js获取系统当前时间展示

获取当前显示的日期 2021年6月1日 星期二

dateTime() {
      let time = new Date();
      let year = time.getFullYear();
      let month = time.getMonth() + 1;
      let date = time.getDate();
      let day = time.getDay();
      let period;
      switch (day) {
        case 0:
          period = "日";
          break;
        case 1:
          period = "一";
          break;
        case 2:
          period = "二";
          break;
        case 3:
          period = "三";
          break;
        case 4:
          period = "四";
          break;
        case 5:
          period = "五";
          break;
        case 6:
          period = "六";
          break;
      }
      return `${year}年${month}月${date}日 星期${period}`;
    },

获取昨天显示的日期 2019-10-13

function getDay(num,) {
    var today = new Date();
    var nowTime = today.getTime();
    var ms = 24*3600*1000*num;
    today.setTime(parseInt(nowTime + ms));
    var oYear = today.getFullYear();
    var oMoth = (today.getMonth() + 1).toString();
    if (oMoth.length <= 1) oMoth = '0' + oMoth;
    var oDay = today.getDate().toString();
    if (oDay.length <= 1) oDay = '0' + oDay;
    return oYear + str + oMoth + str + oDay;
}
var yesterday = getDay(-1, '-');
var today = getDay(0, '-');
console.log(yesterday,today);