ui/quarto_code_tools.html

<script>
window.addEventListener("DOMContentLoaded", () => {
  const showBtn = document.getElementById("quarto-show-all-code");
  const hideBtn = document.getElementById("quarto-hide-all-code");
  if (!showBtn || !hideBtn) return;

  const setAll = (open) => {
    document.querySelectorAll("details.code-fold").forEach((d) => {
      if (open) d.setAttribute("open", "");
      else d.removeAttribute("open");
    });
  };

  // override Quarto's buggy handler
  showBtn.addEventListener("click", (e) => {
    e.preventDefault();
    e.stopImmediatePropagation();
    setAll(true);
  }, true);

  hideBtn.addEventListener("click", (e) => {
    e.preventDefault();
    e.stopImmediatePropagation();
    setAll(false);
  }, true);
});
</script>