hic-et-nunc/assets/js/router.js

const Router = {
  getParam(key) {
    return new URLSearchParams(window.location.search).get(key);
  },

  setParam(key, value) {
    const url = new URL(window.location);
    if (value != null) {
      url.searchParams.set(key, value);
    } else {
      url.searchParams.delete(key);
    }
    history.pushState({}, "", url);
  },
};

window.addEventListener("popstate", () => {
  window.dispatchEvent(new CustomEvent("routechange"));
});