modern toc tweaks

quartz/components/TableOfContents.tsx

@@ -1,38 +1,65 @@
 import { QuartzComponentConstructor, QuartzComponentProps } from "./types"
-import style from "./styles/toc.scss"
-
+import legacyStyle from "./styles/legacyToc.scss"
+import modernStyle from "./styles/toc.scss"
 
 interface Options {
-  layout: 'modern' | 'quartz-3'
+  layout: 'modern' | 'legacy'
 }
 
 const defaultOptions: Options = {
-  layout: 'quartz-3'
+  layout: 'modern'
 }
 
 export default ((opts?: Partial<Options>) => {
   const layout = opts?.layout ?? defaultOptions.layout
-  if (layout === "modern") {
-    return function() {
-      return null // TODO (make this look like nextra)
-    }
-  } else {
-    function TableOfContents({ fileData }: QuartzComponentProps) {
-      if (!fileData.toc) {
-        return null
-      }
-
-      return <details class="toc" open>
-        <summary><h3>Table of Contents</h3></summary>
-        <ul>
-          {fileData.toc.map(tocEntry => <li key={tocEntry.slug} class={`depth-${tocEntry.depth}`}>
-            <a href={`#${tocEntry.slug}`}>{tocEntry.text}</a>
-          </li>)}
-        </ul>
-      </details>
+  function TableOfContents({ fileData }: QuartzComponentProps) {
+    if (!fileData.toc) {
+      return null
     }
 
-    TableOfContents.css = style
-    return TableOfContents
+    return <details class="toc" open>
+      <summary><h3>Table of Contents</h3></summary>
+      <ul>
+        {fileData.toc.map(tocEntry => <li key={tocEntry.slug} class={`depth-${tocEntry.depth}`}>
+          <a href={`#${tocEntry.slug}`} data-for={tocEntry.slug}>{tocEntry.text}</a>
+        </li>)}
+      </ul>
+    </details>
   }
+
+  TableOfContents.css = layout === "modern" ? modernStyle : legacyStyle
+
+  if (layout === "modern") {
+    TableOfContents.afterDOMLoaded = `
+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 init() {
+  const headers = document.querySelectorAll("h1[id], h2[id], h3[id], h4[id], h5[id], h6[id]")
+  headers.forEach(header => observer.observe(header))
+}
+
+init()
+
+document.addEventListener("spa_nav", (e) => {
+  observer.disconnect()
+  init()
+})
+`
+  }
+
+  return TableOfContents
 }) satisfies QuartzComponentConstructor