This is a markdown-it plugin that adds an anchor (i.e., <a name=\"blah\"...>) to headings.

There are other plugins that add an id attribute (valeriangalliat/markdown-it-anchor) or name attribute (leff/markdown-it-named-headers) to headings, but neither of these approches work for adding anchors that are not stripped out of email.

So this extension renders from this...

# My Heading
...
[Link to that heading](#MyHeading).

...to this:

<h1 id="MyHeading">
  <a name="MyHeading" class="markdown-it-headinganchor" href="#"></a>
  My Heading
</h1>
...
<p>
  <a href="#MyHeading">Link to that heading</a>.
</p>

To refer to in heading anchor in a link, remove all spaces from the original text. So, for example, you might have:

## `code` is **bold**
...
[link to the heading](#`code`is**bold**)

Much like other markdown-it plugins, the usage is:

var md = require('markdown-it')();
md.use(require('markdown-it-headinganchor'), {
  anchorClass: 'my-class-name', // default: 'markdown-it-headinganchor'
  addHeadingID: true,           // default: true
  addHeadingAnchor: true,       // default: true
  slugify: function(str, md) {} // default: 'My Heading' -> 'MyHeading'
});
md.render('# My Heading');

Originally developed for use with Markdown Here.