rehype-slug

What is rehype-slug?

The rehype-slug npm package is a plugin for the rehype ecosystem, which is used to process HTML with plugins. This particular plugin automatically adds slugs (URL-friendly identifiers) to headings in HTML documents. These slugs can be used to create anchor links for easy navigation within the document, enhancing the usability and accessibility of web pages.

What are rehype-slug's main functionalities?

Automatic Slug Generation for Headings

This feature automatically generates slugs for each heading in an HTML document. The code sample shows how to use rehype with the rehype-slug plugin to process an HTML string containing a heading, adding an id attribute to the heading based on its content.

const rehype = require('rehype');
const rehypeSlug = require('rehype-slug');

rehype()
  .use(rehypeSlug)
  .process('<h1>Your Heading Here</h1>', function(err, file) {
    console.log(String(file));
  });

Other packages similar to rehype-slug

remark-slug

Similar to rehype-slug, remark-slug is a plugin but for the remark ecosystem, which is used for processing Markdown. It also generates slugs for headings in Markdown documents. While rehype-slug works on HTML, remark-slug is specifically tailored for Markdown, making it suitable for different types of content sources.

gatsby-remark-autolink-headers

This Gatsby plugin automatically adds anchor links to headers in Markdown files processed through Gatsby's remark transformer. It is similar to rehype-slug in functionality but is specifically designed to integrate with the Gatsby static site generator, providing a more seamless experience for Gatsby users compared to using a general-purpose plugin like rehype-slug.

README

rehype-slug

rehype plugin to add ids to headings.

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • unified().use(rehypeSlug[, options])
• Types
• Compatibility
• Security
• Related
• Contribute
• License

What is this?

This package is a unified (rehype) plugin to add ids to headings. It looks for headings (so <h1> through <h6>) that do not yet have ids and adds id attributes to them based on the text they contain. The algorithm that does this is github-slugger, which matches how GitHub works.

unified is a project that transforms content with abstract syntax trees (ASTs). rehype adds support for HTML to unified. hast is the HTML AST that rehype uses. This is a rehype plugin that adds ids to headings in the AST.

When should I use this?

This plugin is useful when you have relatively long documents and you want to be able to link to particular sections.

A different plugin, rehype-autolink-headings, adds links to these headings back to themselves, which is useful as it lets users more easily link to particular sections.

Install

This package is ESM only. In Node.js (version 12.20+, 14.14+, or 16.0+), install with npm:

npm install rehype-slug

In Deno with esm.sh:

import rehypeSlug from 'https://esm.sh/rehype-slug@5'

In browsers with esm.sh:

<script type="module">
  import rehypeSlug from 'https://esm.sh/rehype-slug@5?bundle'
</script>

Use

Say we have the following file example.html:

<h1 id=some-id>Lorem ipsum</h1>
<h2>Dolor sit amet 😪</h2>
<h3>consectetur &amp; adipisicing</h3>
<h4>elit</h4>
<h5>elit</h5>

And our module example.js looks as follows:

import {read} from 'to-vfile'
import {rehype} from 'rehype'
import rehypeSlug from 'rehype-slug'

const file = await rehype()
  .data('settings', {fragment: true})
  .use(rehypeSlug)
  .process(await read('example.html'))

console.log(String(file))

Now, running node example.js yields:

<h1 id="some-id">Lorem ipsum</h1>
<h2 id="dolor-sit-amet-">Dolor sit amet 😪</h2>
<h3 id="consectetur--adipisicing">consectetur &#x26; adipisicing</h3>
<h4 id="elit">elit</h4>
<h5 id="elit-1">elit</h5>

API

This package exports no identifiers. The default export is rehypeSlug.

unified().use(rehypeSlug[, options])

Add ids to headings.

options

Configuration (optional).

options.prefix

Prefix to add in front of ids (string, default: '').

Types

This package is fully typed with TypeScript. It exports the additional type Options.

Compatibility

Projects maintained by the unified collective are compatible with all maintained versions of Node.js. As of now, that is Node.js 12.20+, 14.14+, and 16.0+. Our projects sometimes work with older versions, but this is not guaranteed.

This plugin works with rehype-parse version 1+, rehype-stringify version 1+, rehype version 1+, and unified version 4+.

Security

Use of rehype-slug can open you up to a cross-site scripting (XSS) attack as it sets id attributes on headings, which causes what is known as “DOM clobbering”. Please use rehype-sanitize and see its Example: headings (DOM clobbering) for information on how to properly solve it.

Related

• rehype-autolink-headings — add links to headings with IDs back to themselves

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