mdast-util-toc

mdast utility to generate table of contents.

Install

This package is ESM only: Node 12+ is needed to use it and it must be imported instead of required.

npm:

npm install mdast-util-toc

Use

Dependencies:

/** @typedef {import('mdast').Root} Root */
import {u} from 'unist-builder'
import {toc} from 'mdast-util-toc'

Now running:

const tree = /** @type {Root} */ (
  u('root', [
    u('heading', {depth: 1}, [u('text', 'Alpha')]),
    u('heading', {depth: 2}, [u('text', 'Bravo')]),
    u('heading', {depth: 3}, [u('text', 'Charlie')]),
    u('heading', {depth: 2}, [u('text', 'Delta')])
  ])
)

const table = toc(tree)

Yields:

{
  index: null,
  endIndex: null,
  map: {
    type: 'list',
    ordered: false,
    spread: true,
    children: [ { type: 'listItem', spread: true, children: [Array] } ]
  }
}

API

This package exports the following identifiers: toc. There is no default export.

toc(tree[, options])

Generate a Table of Contents from a tree.

Looks for the first heading matching options.heading (case insensitive), and returns a table of contents (list) for all following headings. If no heading is specified, creates a table of contents for all headings in tree. tree is not changed.

Links to headings are based on GitHub’s style. Only top-level headings (those not in blockquotes or lists), are used. This default behavior can be changed by passing parents.

options

options.heading

Heading to look for (string), wrapped in new RegExp('^(' + value + ') , 'i').

options.maxDepth

Maximum heading depth to include in the table of contents (number, default: 6), This is inclusive: when set to 3, level three headings are included (those with three hashes, ###).

options.skip

Headings to skip (string, optional), wrapped in new RegExp('^(' + value + ') , 'i'). Any heading matching this expression will not be present in the table of contents.

options.tight

Whether to compile list-items tightly (boolean?, default: false).

options.ordered

Whether to compile list-items as an ordered list (boolean?, default: false).

options.prefix

Add a prefix to links to headings in the table of contents (string?, default: null). Useful for example when later going from mdast to hast and sanitizing with hast-util-sanitize.

options.parents

Allows headings to be children of certain node types (default: the to toc given tree, to only allow top-level headings). Internally, uses unist-util-is to check, so parents can be any is-compatible test.

For example, this would allow headings under either root or blockquote to be used:

toc(tree, {parents: ['root', 'blockquote']})

Returns

An object representing the table of contents.

Properties

• index (number?) — Index of the node right after the table of contents heading. -1 if no heading was found, null if no heading was given
• endIndex (number?) — Index of the first node after heading that is not part of its section. -1 if no heading was found, null if no heading was given, same as index if there are no nodes between heading and the first heading in the TOC
• map (Node?) — List representing the generated table of contents. null if no table of contents could be created, either because no heading was found or because no following headings were found

Security

Use of mdast-util-toc does not involve hast, user content, or change the tree, so there are no openings for cross-site scripting (XSS) attacks.

Injecting map into the syntax tree may open you up to XSS attacks as existing nodes are copied into the table of contents. The following example shows how an existing script is copied into the table of contents.

For the following Markdown:

# Alpha

## Bravo<script>alert(1)</script>

## Charlie

Yields in map:

-   [Alpha](#alpha)

    -   [Bravo<script>alert(1)</script>](#bravoscriptalert1script)
    -   [Charlie](#charlie)

Always use hast-util-santize when transforming to hast.

Related

• github-slugger — Generate a slug just like GitHub does
• unist-util-visit — visit nodes
• unist-util-visit-parents — like visit, but with a stack of parents

Contribute

See contributing.md in syntax-tree/.github for ways to get started. See support.md for ways to get help.

This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.

License

MIT © Jonathan Haines