const deepCopy = obj =>
  typeof obj !== 'object' || obj === null
    ? obj
    : Object.keys(obj).reduce((acc, key) => {
        acc[key] = deepCopy(obj[key])
        return acc
      }, new obj.constructor())

let activeDiv = null;
divs.forEach((div) => {
  div.addEventListener('click', () => {
    if (activeDiv === div) return;
    activeDiv?.classList.remove('activeItem');
    div.classList.add('activeItem');
    activeDiv = div;
  });
});