获取昨天 2022-08-18

function getToday() {
      //获取当前日期
      let myDate = new Date();
      let nowY = myDate.getFullYear();
      let nowM = myDate.getMonth() + 1;
      let nowD = myDate.getDate()-1;
      let endDate =
        nowY +
        "-" +
        (nowM < 10 ? "0" + nowM : nowM) +
        "-" +
        (nowD < 10 ? "0" + nowD : nowD); //当前日期
      return endDate;
}

获取30天前  2022-07-20

function getThreeDaysAgo() {
      let myDate = new Date();
      let lw = new Date(myDate - 1000 * 60 * 60 * 24 * 30); //最后一个数字30可改，30天的意思
      let lastY = lw.getFullYear();
      let lastM = lw.getMonth() + 1;
      let lastD = lw.getDate();
      let startData =
        lastY +
        "-" +
        (lastM < 10 ? "0" + lastM : lastM) +
        "-" +
        (lastD < 10 ? "0" + lastD : lastD); //三十天之前日期
      return startData;
    }