rehype-autolink-headings

What is rehype-autolink-headings?

The rehype-autolink-headings package is a plugin for the rehype ecosystem that automatically adds links to headings in HTML documents. This is particularly useful for generating anchor links for headings in markdown files that are converted to HTML, making it easier to navigate through long documents.

What are rehype-autolink-headings's main functionalities?

Basic Usage

This code demonstrates the basic usage of rehype-autolink-headings. It processes an HTML string containing headings and automatically adds anchor links to those headings.

const rehype = require('rehype');
const rehypeAutolinkHeadings = require('rehype-autolink-headings');

rehype()
  .use(rehypeAutolinkHeadings)
  .process('<h1>Title</h1><h2>Subtitle</h2>', function (err, file) {
    if (err) throw err;
    console.log(String(file));
  });

Customizing Link Properties

This example shows how to customize the behavior of the links added to the headings. The 'behavior' option is set to 'wrap', which wraps the heading text with the anchor link.

const rehype = require('rehype');
const rehypeAutolinkHeadings = require('rehype-autolink-headings');

rehype()
  .use(rehypeAutolinkHeadings, { behavior: 'wrap' })
  .process('<h1>Title</h1><h2>Subtitle</h2>', function (err, file) {
    if (err) throw err;
    console.log(String(file));
  });

Adding Custom Properties to Links

This example demonstrates how to add custom properties to the generated links. Here, a custom class name 'custom-class' is added to the anchor links.

const rehype = require('rehype');
const rehypeAutolinkHeadings = require('rehype-autolink-headings');

rehype()
  .use(rehypeAutolinkHeadings, { properties: { className: 'custom-class' } })
  .process('<h1>Title</h1><h2>Subtitle</h2>', function (err, file) {
    if (err) throw err;
    console.log(String(file));
  });

Other packages similar to rehype-autolink-headings

remark-autolink-headings

remark-autolink-headings is a plugin for the remark ecosystem that adds links to headings in markdown documents. It is similar to rehype-autolink-headings but is used within the remark ecosystem, which is focused on processing markdown rather than HTML.

markdown-it-anchor

markdown-it-anchor is a plugin for the markdown-it parser that automatically adds anchor links to headings in markdown documents. It provides similar functionality to rehype-autolink-headings but is designed to work with the markdown-it parser.

gatsby-remark-autolink-headers

gatsby-remark-autolink-headers is a Gatsby plugin that adds anchor links to headings in markdown files processed by Gatsby. It is similar to rehype-autolink-headings but is specifically designed for use within the Gatsby framework.

README

rehype-autolink-headings

rehype plugin to automatically add links to headings (h1-h6).

Install

npm:

npm install rehype-autolink-headings

Use

Say we have the following file, fragment.html:

<h1>Lorem ipsum 😪</h1>
<h2>dolor—sit—amet</h2>
<h3>consectetur &amp; adipisicing</h3>
<h4>elit</h4>
<h5>elit</h5>

And our script, example.js, looks as follows:

var fs = require('fs')
var rehype = require('rehype')
var slug = require('rehype-slug')
var link = require('rehype-autolink-headings')

var doc = fs.readFileSync('fragment.html')

rehype()
  .data('settings', {fragment: true})
  .use(slug)
  .use(link)
  .process(doc, function(err, file) {
    if (err) throw err
    console.log(String(file))
  })

Now, running node example yields:

<h1 id="lorem-ipsum-"><a aria-hidden="true" href="#lorem-ipsum-"><span class="icon icon-link"></span></a>Lorem ipsum 😪</h1>
<h2 id="dolorsitamet"><a aria-hidden="true" href="#dolorsitamet"><span class="icon icon-link"></span></a>dolor—sit—amet</h2>
<h3 id="consectetur--adipisicing"><a aria-hidden="true" href="#consectetur--adipisicing"><span class="icon icon-link"></span></a>consectetur &#x26; adipisicing</h3>
<h4 id="elit"><a aria-hidden="true" href="#elit"><span class="icon icon-link"></span></a>elit</h4>
<h5 id="elit-1"><a aria-hidden="true" href="#elit-1"><span class="icon icon-link"></span></a>elit</h5>

API

rehype().use(link[, options])

Add links to headings (h1-h6) with an id.

Note: this plugin expects ids to already exist on headings. One way to add those automatically, is rehype-slug (see example).

options

options.behavior

How to create links (string, default: 'prepend').

• 'prepend' — inject link before the heading text
• 'append' — inject link after the heading text
• 'wrap' — wrap the whole heading text with the link
• 'before' — insert link before the heading
• 'after' — insert link after the heading

Supplying wrap will ignore any value defined by the content option. Supplying prepend, append, or wrap will ignore the group option.

options.properties

Extra properties to set on the link (Object?). Defaults to {ariaHidden: true, tabIndex: -1} when in 'prepend' or 'append' mode.

options.content

hast nodes to insert in the link (Function|Node|Children). By default, the following is used:

{
  type: 'element',
  tagName: 'span',
  properties: {className: ['icon', 'icon-link']},
  children: []
}

If behavior is wrap, then content is ignored.

If content is a function, it’s called with the current heading (Element) and should return one or more nodes:

var toString = require('hast-util-to-string')
var h = require('hastscript')

// …

function content(node) {
  return [
    h('span.visually-hidden', 'Read the “', toString(node), '” section'),
    h('span.icon.icon-link', {ariaHidden: true})
  ]
}

options.group

hast node to wrap the heading and link with (Function|Node), if behavior is before or after. There is no default.

If behavior is prepend, append, or wrap, then group is ignored.

If group is a function, it’s called with the current heading (Element) and should return a hast node.

var h = require('hastscript')

// …

function group(node) {
  return h('.heading-' + node.charAt(1) + '-group')
}

Security

Use of rehype-autolink-headings can open you up to a cross-site scripting (XSS) attack if you pass user provided content in properties or content.

Always be wary of user input and use rehype-sanitize.

Related

• rehype-slug — Add ids to headings
• rehype-highlight — Syntax highlight code blocks
• rehype-toc — Add a table of contents (TOC)

Contribute

See contributing.md in rehypejs/.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 © Titus Wormer