| |
| (function () { |
| var toc = document.querySelector(".toc"); |
| var heads = Array.prototype.filter.call( |
| document.querySelectorAll(".article h2"), |
| function (h) { return !h.closest(".stat"); } |
| ); |
| if (!toc || heads.length < 2) { if (toc) toc.remove(); return; } |
|
|
| var used = {}; |
| var items = heads.map(function (h) { |
| var id = h.id || h.textContent.toLowerCase().replace(/[^a-z0-9]+/g, "-").replace(/^-|-$/g, "") || "section"; |
| while (used[id]) id += "-2"; |
| used[id] = true; |
| h.id = id; |
| return '<li><a href="#' + id + '">' + h.innerHTML.replace(/<[^>]+>/g, "") + "</a></li>"; |
| }); |
|
|
| toc.innerHTML = |
| '<details open><summary>In this article</summary><ol>' + items.join("") + "</ol></details>"; |
|
|
| |
| var details = toc.querySelector("details"); |
| if (window.matchMedia("(max-width: 72rem)").matches) details.removeAttribute("open"); |
|
|
| var links = toc.querySelectorAll("a"); |
| if ("IntersectionObserver" in window) { |
| var io = new IntersectionObserver(function (entries) { |
| entries.forEach(function (e) { |
| if (!e.isIntersecting) return; |
| links.forEach(function (a) { |
| a.classList.toggle("on", a.getAttribute("href") === "#" + e.target.id); |
| }); |
| }); |
| }, { rootMargin: "-80px 0px -70% 0px" }); |
| heads.forEach(function (h) { io.observe(h); }); |
| } |
| })(); |
|
|
