hugo-theme-hello-friend/source/js/menu.js

const container = document.querySelector(".container");
const menu = document.querySelector(".menu");
const mobileMenuTrigger = document.querySelector(".menu-trigger");
const desktopMenu = document.querySelector(".menu__inner--desktop");
const desktopMenuTrigger = document.querySelector(".menu__sub-inner-more-trigger");
const menuMore = document.querySelector(".menu__sub-inner-more");
const mobileQuery = getComputedStyle(document.body).getPropertyValue("--phoneWidth");
const isMobile = () => window.matchMedia(mobileQuery).matches;
const isMobileMenu = () => {
  mobileMenuTrigger && mobileMenuTrigger.classList.toggle("hidden", !isMobile());
  menu && menu.classList.toggle("hidden", isMobile());
  menuMore && menuMore.classList.toggle("hidden", !isMobile());
};

// Common

menu && menu.addEventListener("click", e => e.stopPropagation());
menuMore && menuMore.addEventListener("click", e => e.stopPropagation());

isMobileMenu();

document.body.addEventListener("click", () => {
  if (!isMobile() && !menuMore.classList.contains("hidden")) {
    menuMore.classList.add("hidden");
  } else if (isMobile() && !menu.classList.contains("hidden")) {
    menu.classList.add("hidden");
  }
});

window.addEventListener("resize", isMobileMenu);

// Mobile menu

mobileMenuTrigger &&
  mobileMenuTrigger.addEventListener("click", e => {
    e.stopPropagation();
    menu && menu.classList.toggle("hidden");
  });

// Desktop menu

desktopMenuTrigger &&
  desktopMenuTrigger.addEventListener("click", e => {
    e.stopPropagation();
    menuMore && menuMore.classList.toggle("hidden");

    if (menuMore.getBoundingClientRect().right > container.getBoundingClientRect().right) {
      menuMore.style.left = "auto";
      menuMore.style.right = 0;
    }
  });