rehype-extract-toc

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

How to install

yarn 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
}