Get and set cookies on first user visit

firstVisitCookies.js

function setCookie(name, value, days) {
  var expires = '';
  if (days) {
      let date = new Date();
      date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
      expires = '; expires=' + date.toUTCString();
  }
  document.cookie = name + '=' + (value || '')  + expires + '; path=/';
}

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

(function() {
  let firstVisitCookie = getCookie('firstVisitCookie');
  let firstVisitModal = $('#firstViisitModal');

  if (! firstVisitCookie && firstVisitModal.length) {
    let subscribeForm = firstVisitModal.find('form');
    firstVisitModal.modal('show');
    subscribeForm.on('submit', function() {
      setCookie('firstVisitCookie', '1', 30);
    });
    firstVisitModal.on('hide.bs.modal', function() {
      setCookie('firstVisitCookie', '1', 30);
    });
  }
}());