toc for md

const toc = document.getElementById('table-of-contents');
for (const x of document.querySelectorAll('h2, h3')) {
  const id = x.innerText.replaceAll(/[^a-z0-9]/gi,'');
  x.id = id;
  const item = `<li><a href="#${id}">${x.innerText}</a></li>`;
  switch (x.tagName.toLowerCase()) {
    case "h2": toc.insertAdjacentHTML('beforeend', `${item}<ul></ul>`); break;
    case "h3": [...toc.querySelectorAll('ul')]?.pop()?.insertAdjacentHTML('beforeend', item); break;
  }
}

//from https://taylor.town/toc-snippet