The date format is wrong when JS reads Excel

Problem : I encountered a problem in the process of working on the project. When importing excel data, I found that the format of the date was wrong. The expected effect is 2022/1/2, but the effect after importing is 44563. After consulting the data, it is found that 44563 represents the number of days between January 1, 1900 and January 2, 2022.

Method 1 (not recommended)

formatDate(numb, format) {
  const time = new Date((numb - 1) * 24 * 3600000 + 1);
  time.setYear(time.getFullYear() - 70)
  const year = time.getFullYear() ;
  const month = time.getMonth() + 1 ;
  const date = time.getDate() - 1 ;
  return year + format + (month < 10 ? '0' + month : month) + format + (date < 10 ? '0' + date : date)
},

This method has certain flaws, and there will be deviations at certain specific times. For example, on the day of 2022/03/08, after importing the input, it will display 2022/03/07. One day less than the original data.

Method 2 (recommended)

formatDate(numb, format) {
        //参数numb是间隔天数，format是自定义的日期分隔符。
        console.log(numb)
        //打印出来的结果是44563，表示1900年1月1日到当前日期的天数
        let getDay = numb - 1
        let t = Math.round((getDay - Math.floor(getDay)) * 24 * 60 * 60)
        //当导入的excel日期中包含了时分秒，t则表示小数点后面的时间
        let time = new Date(1900, 0, getDay, 0, 0, t);
        //getDay是从1900开始计算的，因此new Date()的第一个参数是1900
        let year = time.getFullYear();
        let month = time.getMonth() + 1;
        let date = time.getDate();
        return year + format + (month < 10 ? "0" + month : month) + format + (date < 10 ? "0" + date : date);
    },

This method can perfectly solve the problem of wrong date format when JS reads Excel, and I hope it can be helpful to everyone.