addAnnouncementFromPool = () => {
  const [first, ...rest] = currPool;
  if (first) {
    announcements.push(first);
    currPool = rest;
  } else {
    console.warn("no more announcements in pool, generating a new one");
    addMockAnnouncement();
  }
}
addAnnoucementFromPool
will take into announcementsPool to push a new announcements
if there are no more announcement left in the pool, it will use addMockAnnouncement to generate a new one