Flet
markdown-it-github-headings
Add GitHub style anchor tags to headers
Install
npm install markdown-it-github-headingsUsage
var md = require('markdown-it')()
.use(require('markdown-it-github-headings'), options)
Options and Defaults
The defaults will make the heading anchors behave as close to how GitHub behaves as possible.
| Name | Description | Default |
|---|---|---|
className |
name of the class that will be added to the anchor tag | anchor |
prefixHeadingIds |
add a prefix to each heading ID. (see security note below) | true |
prefix |
if prefixHeadingIds is true, use this string to prefix each ID. |
user-content- |
enableHeadingLinkIcons |
Adds the icon <svg aria-hidden="true" class="octicon octicon-link" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg> next to each heading | true |
linkIcon |
If enableHeadingLinkIcons is true, use this to supply a custom icon (or anything really) |
<svg aria-hidden="true" class="octicon octicon-link" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg> |
resetSlugger |
reset the slugger counter between .render calls for duplicate headers. (See tests for example) | true |
Why should I prefix heading IDs?
When using user generated content, its possible to run into DOM Clobbering when heading IDs are generated. Since IDs are used by JavaScript and CSS, a user could craft a page that breaks functionality or styles. A good way to avoid clobbering is to add a prefix to every generated ID to ensure they cannot overlap with existing IDs.
If you have full control over the content, there is less of a risk, but be aware that strange bugs related to DOM Clobbering are still possible!
For more information, here are some good resources on the topic:
- User-generated content and DOM clobbering
- In the DOM, no one will hear you scream
- A discussion about GitHub implementation
- An open issue on markdown-it repo
But the prefixes make links look real gross.
One solution is to write some client side JavaScript to force non-prefixed hashes to jump to prefixed anchors. This is how its handled on GitHub and npmjs.com.
Check out marky-deep-links for an example (works great with browserify or webpack).
Contributing
Contributions welcome! Please read the contributing guidelines first.