rehype-extract-toc

This is a rehype plugin which attaches a document's table of contents to the VFile.

How to install

pnpm add @stefanprobst/rehype-extract-toc

How to use

import { rehype } from "rehype";
import withSlugs from "rehype-slug";
import withToc from "@stefanprobst/rehype-extract-toc";

const processor = rehype().use(withSlugs).use(withToc);

const file = processor.processSync(doc);

console.dir(file.data.toc, { depth: null });

The table of contents will be attached to the resulting VFile's data.toc property. It has the following shape:

interface TocEntry {
	value: string;
	depth: number;
	id?: string;
	children?: Array<TocEntry>;
}

type Toc = Array<TocEntry>;

Note that this plugin does not generate any ids, you will probably want to combine it with rehype-slug.

How you render the table of contents is up to you.

How to use with MDX

When transforming MDX documents, you can expose the table of contents as a named export, which defaults to tableOfContents.

import { compile } from "@mdx-js/mdx";
import withSlugs from "rehype-slug";
import withToc from "@stefanprobst/rehype-extract-toc";
import withTocExport from "@stefanprobst/rehype-extract-toc/mdx";

async function run() {
	const file = await compile(doc, {
		rehypePlugins: [
			withSlugs,
			withToc,
			withTocExport,
			/** Optionally, provide a custom name for the export. */
			// [withTocExport, { name: 'toc' }],
		],
	});

	console.log(String(file));
}

run();

If you are using TypeScript, you can add typings with:

/** mdx.d.ts (should be referenced in `tsconfig.json#include`) */
declare module '*.mdx' {
  import type { MDXProps } from 'mdx/types'
  import type { Toc } from '@stefanprobst/rehype-extract-toc'

  export const tableOfContents: Toc
  export default function MDXContent(props: MDXProps): JSX.Element
}