const navigationItems = document.querySelectorAll(".nav__item");

navigationItems.forEach((item) => {
  item.onclick = (elem) => {
    navigationItems.forEach((item2) =>
      item2.classList.remove("nav__item_active")
    );

    !item.classList.contains("nav__item_active") &&
      item.classList.add("nav__item_active");
  };
});