collapsible toc

quartz/components/scripts/toc.inline.ts

@@ -0,0 +1,35 @@
+const bufferPx = 150
+const observer = new IntersectionObserver(entries => {
+  for (const entry of entries) {
+    const slug = entry.target.id
+    const tocEntryElement = document.querySelector(`a[data-for="${slug}"]`)
+    const windowHeight = entry.rootBounds?.height
+    if (windowHeight && tocEntryElement) {
+      if (entry.boundingClientRect.y < windowHeight) {
+        tocEntryElement.classList.add("in-view")
+      } else {
+        tocEntryElement.classList.remove("in-view")
+      }
+    }
+  }
+})
+
+function toggleCollapsible(this: HTMLElement) {
+  this.classList.toggle("collapsed")
+  const content = this.nextElementSibling as HTMLElement
+  content.classList.toggle("collapsed")
+  content.style.maxHeight = content.style.maxHeight === "0px" ? content.scrollHeight + "px" : "0px"
+}
+
+document.addEventListener("nav", () => {
+  const toc = document.getElementById("toc")!
+  const content = toc.nextElementSibling as HTMLElement
+  content.style.maxHeight = content.scrollHeight + "px"
+  toc.removeEventListener("click", toggleCollapsible)
+  toc.addEventListener("click", toggleCollapsible)
+
+  // update toc entry highlighting
+  observer.disconnect()
+  const headers = document.querySelectorAll("h1[id], h2[id], h3[id], h4[id], h5[id], h6[id]")
+  headers.forEach(header => observer.observe(header))
+})