toc

quartz/plugins/transformers/toc.ts

@@ -0,0 +1,72 @@
+import { PluggableList } from "unified"
+import { QuartzTransformerPlugin } from "../types"
+import { Root } from "mdast"
+import { visit } from "unist-util-visit"
+import { toString } from "mdast-util-to-string"
+import { slugAnchor } from "../../path"
+
+export interface Options {
+  maxDepth: 1 | 2 | 3 | 4 | 5 | 6,
+  minEntries: 1,
+  showByDefault: boolean
+}
+
+const defaultOptions: Options = {
+  maxDepth: 3,
+  minEntries: 1,
+  showByDefault: true,
+}
+
+interface TocEntry {
+  depth: number,
+  text: string,
+  slug: string
+}
+
+export class TableOfContents extends QuartzTransformerPlugin {
+  name = "TableOfContents"
+  opts: Options
+
+  constructor(opts?: Partial<Options>) {
+    super()
+    this.opts = { ...defaultOptions, ...opts }
+  }
+
+  markdownPlugins(): PluggableList {
+    return [() => {
+      return async (tree: Root, file) => {
+        const display = file.data.frontmatter?.enableToc ?? this.opts.showByDefault
+        if (display) {
+          const toc: TocEntry[] = []
+          let highestDepth: number = this.opts.maxDepth
+          visit(tree, 'heading', (node) => {
+            if (node.depth <= this.opts.maxDepth) {
+              const text = toString(node)
+              highestDepth = Math.min(highestDepth, node.depth)
+              toc.push({
+                depth: node.depth,
+                text,
+                slug: slugAnchor.slug(text)
+              })
+            }
+          })
+
+          if (toc.length > this.opts.minEntries) {
+            file.data.toc = toc.map(entry => ({ ...entry, depth: entry.depth - highestDepth }))
+          }
+        }
+      }
+    }]
+  }
+
+  htmlPlugins(): PluggableList {
+    return []
+  }
+}
+
+declare module 'vfile' {
+  interface DataMap {
+    toc: TocEntry[]
+  }
+}
+