markdown-it-footnote

Footnotes plugin for markdown-it markdown parser.

v2.+ requires markdown-it v5.+, see changelog.

Markup is based on pandoc definition.

Normal footnote:

Here is a footnote reference,[^1] and another.[^longnote]

[^1]: Here is the footnote.

[^longnote]: Here's one with multiple blocks.

    Subsequent paragraphs are indented to show that they
belong to the previous footnote.

html:

 <p>Here is a footnote reference,<sup class="footnote-ref"><a href="#fn1" id="fnref1">[1]</a></sup> and another.<sup class="footnote-ref"><a href="#fn2" id="fnref2">[2]</a></sup></p>
<p>This paragraph won’t be part of the note, because it
isn’t indented.</p>
<hr class="footnotes-sep">
<section class="footnotes">
<ol class="footnotes-list">
<li id="fn1"  class="footnote-item"><p>Here is the footnote. <a href="#fnref1" class="footnote-backref">↩</a></p>
</li>
<li id="fn2"  class="footnote-item"><p>Here’s one with multiple blocks.</p>
<p>Subsequent paragraphs are indented to show that they
belong to the previous footnote. <a href="#fnref2" class="footnote-backref">↩</a></p>
</li>
</ol>
</section>

Inline footnote:

Here is an inline note.^[Inlines notes are easier to write, since
you don't have to pick an identifier and move down to type the
note.]

html:

 <p>Here is an inline note.<sup class="footnote-ref"><a href="#fn1" id="fnref1">[1]</a></sup></p>
<hr class="footnotes-sep">
<section class="footnotes">
<ol class="footnotes-list">
<li id="fn1"  class="footnote-item"><p>Inlines notes are easier to write, since
you don’t have to pick an identifier and move down to type the
note. <a href="#fnref1" class="footnote-backref">↩</a></p>
</li>
</ol>
</section>

Install

node.js, browser:

 npm install markdown-it-footnote --save
bower install markdown-it-footnote --save

Use

 var md = require('markdown-it')()
            .use(require('markdown-it-footnote'));

md.render(/*...*/) // See examples above

Differences in browser. If you load script directly into the page, without
package system, module will add itself globally as window.markdownitFootnote.

Customize

If you want to customize the output, you'll need to replace the template
functions. To see which templates exist and their default implementations,
look in index.js. The API of these template functions is out of
scope for this plugin's documentation; you can read more about it in the
markdown-it
documentation.

To demonstrate with an example, here is how you might replace the <hr> that
this plugin emits by default with an <h4> emitted by your own template
function override:

 const md = require('markdown-it')().use(require('markdown-it-footnote'));

md.renderer.rules.footnote_block_open = () => (
  '<h4 class="mt-3">Footnotes</h4>\n' +
  '<section class="footnotes">\n' +
  '<ol class="footnotes-list">\n'
);

Here's another example that customizes footnotes for epub books:

 const backrefLabel = 'back to text';

const epubRules = {
  footnote_ref: ['<a', '<a epub:type="noteref"'],
  footnote_open: ['<li', '<li epub:type="footnote"'],
  footnote_anchor: ['<a', `<a aria-label="${backrefLabel}"`],
}

Object.keys(epubRules).map(rule => {
  let defaultRender = md.renderer.rules[rule];
  md.renderer.rules[rule] = (tokens, idx, options, env, self) => {
    return defaultRender(tokens, idx, options, env, self).replace(...epubRules[rule]);
  }
})

License

MIT