pos_xcx/utils/date.js

 function addDays(date, days,seperator='-') {
    let oDate = new Date(date).valueOf();
    let nDate = oDate + days * 24 * 3600 * 1000;
    nDate = new Date(nDate);
    let y = nDate.getFullYear().toString().padStart(2, 0);
    let m = (nDate.getMonth() + 1).toString().padStart(2, 0);
    let d = nDate.getDate().toString().padStart(2, 0);
    return `${y}${seperator}${m}${seperator}${d}`
  }