utils.js

function getDate() {
  return parseDate(new Date());
}

function parseDate(date) {
  var dd = String(date.getDate()).padStart(2, '0');
  var mm = String(date.getMonth() + 1).padStart(2, '0'); //January is 0!
  var yyyy = date.getFullYear();
  today = mm + '/' + dd + '/' + yyyy;
  return today
}

function modifyDate(date, modifier) {
  let dateObj = new Date(date)
  dateObj.setDate(dateObj.getDate() + modifier)
  return parseDate(dateObj)
}
function getMonthName(date){
  const monthNames = ["Styczeń", "Luty", "Marzec", "Kwieceń", "Maj", "Czerwiec",
    "Lipiec", "Sierpień", "Wrzesień", "Październik", "Listopad", "Grudzień"
  ];
  return monthNames[date.getMonth()]
}

function getDayName(date){
  const dayNames = ["niedziela","poniedziałek","wtorek","sroda","czwartek","piątek","sobota"]
  return dayNames[date.getDay()]
}
var getJSON = function (url, callback) {
  var xhr = new XMLHttpRequest();
  xhr.open('GET', url, true);
  xhr.responseType = 'json';
  xhr.onload = function () {
    var status = xhr.status;
    if (status === 200) {
      callback(null, xhr.response);
    } else {
      callback(status, xhr.response);
    }
  };
  xhr.send();
};

function getCookie(cname) {
  var name = cname + "=";
  var decodedCookie = decodeURIComponent(document.cookie);
  var ca = decodedCookie.split(';');
  for (var i = 0; i < ca.length; i++) {
    var c = ca[i];
    while (c.charAt(0) == ' ') {
      c = c.substring(1);
    }
    if (c.indexOf(name) == 0) {
      return c.substring(name.length, c.length);
    }
  }
  return "";
}

function setCookie(cname, cvalue, exdays) {
  var d = new Date();
  d.setTime(d.getTime() + (exdays * 24 * 60 * 60 * 1000));
  var expires = "expires=" + d.toUTCString();
  document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}