micromark-extension-gfm

micromark extensions to support GitHub flavored markdown (GFM).

Contents

• What is this?
• When to use this
• Install
• Use
• API
  • gfm(options?)
  • gfmHtml(options?)
  • Options
  • HtmlOptions
• Bugs
• Authoring
• HTML
• CSS
• Syntax
• Types
• Compatibility
• Security
• Contribute
• License

What is this?

This package contains extensions that add support for all features enabled by GFM to micromark. It supports autolink literals, footnotes, strikethrough, tables, tagfilter, and tasklists.

When to use this

This project is useful when you want to support GFM in markdown.

You can use these extensions when you are working with micromark. Alternatively, you can also use the underlying features separately:

• micromark-extension-gfm-autolink-literal — support GFM autolink literals
• micromark-extension-gfm-footnote — support GFM footnotes
• micromark-extension-gfm-strikethrough — support GFM strikethrough
• micromark-extension-gfm-table — support GFM tables
• micromark-extension-gfm-tagfilter — support GFM tagfilter
• micromark-extension-gfm-task-list-item — support GFM tasklists

When you need a syntax tree, combine this package with mdast-util-gfm.

All these packages are used in remark-gfm, which focusses on making it easier to transform content by abstracting these internals away.

Install

This package is ESM only. In Node.js (version 16+), install with npm:

npm install micromark-extension-gfm

In Deno with esm.sh:

import {gfm, gfmHtml} from 'https://esm.sh/micromark-extension-gfm@3'

In browsers with esm.sh:

<script type="module">
  import {gfm, gfmHtml} from 'https://esm.sh/micromark-extension-gfm@3?bundle'
</script>

Use

Say our document example.md contains:

# GFM

## Autolink literals

www.example.com, https://example.com, and [email protected].

## Footnote

A note[^1]

[^1]: Big note.

## Strikethrough

~one~ or ~~two~~ tildes.

## Table

| a | b  |  c |  d  |
| - | :- | -: | :-: |

## Tag filter

<plaintext>

## Tasklist

* [ ] to do
* [x] done

…and our module example.js looks as follows:

import fs from 'node:fs/promises'
import {micromark} from 'micromark'
import {gfm, gfmHtml} from 'micromark-extension-gfm'

const output = micromark(await fs.readFile('example.md'), {
  allowDangerousHtml: true,
  extensions: [gfm()],
  htmlExtensions: [gfmHtml()]
})

console.log(output)

…now running node example.js yields:

<h1>GFM</h1>
<h2>Autolink literals</h2>
<p><a href="http://www.example.com">www.example.com</a>, <a href="https://example.com">https://example.com</a>, and <a href="mailto:[email protected]">[email protected]</a>.</p>
<h2>Footnote</h2>
<p>A note<sup><a href="#user-content-fn-1" id="user-content-fnref-1" data-footnote-ref="" aria-describedby="footnote-label">1</a></sup></p>
<h2>Strikethrough</h2>
<p><del>one</del> or <del>two</del> tildes.</p>
<h2>Table</h2>
<table>
<thead>
<tr>
<th>a</th>
<th align="left">b</th>
<th align="right">c</th>
<th align="center">d</th>
</tr>
</thead>
</table>
<h2>Tag filter</h2>
&lt;plaintext>
<h2>Tasklist</h2>
<ul>
<li><input type="checkbox" disabled="" /> to do</li>
<li><input type="checkbox" disabled="" checked="" /> done</li>
</ul>
<section data-footnotes="" class="footnotes"><h2 id="footnote-label" class="sr-only">Footnotes</h2>
<ol>
<li id="user-content-fn-1">
<p>Big note. <a href="#user-content-fnref-1" data-footnote-backref="" class="data-footnote-backref" aria-label="Back to content">↩</a></p>
</li>
</ol>
</section>

API

This package exports the identifiers gfm and gfmHtml. There is no default export.

The separate extensions support the development condition. Run node --conditions development module.js to get instrumented dev code. Without this condition, production code is loaded.

gfm(options?)

Create an extension for micromark to enable GFM syntax.

Parameters

• options (Options, optional) — configuration; passed to micromark-extens-gfm-strikethrough

Returns

Extension for micromark that can be passed in extensions to enable GFM syntax (Extension).

gfmHtml(options?)

Create an extension for micromark to support GFM when serializing to HTML.

Parameters

• options (HtmlOptions, optional) — configuration; passed to micromark-extens-gfm-footnote

Returns

Extension for micromark that can be passed in htmlExtensions to support GFM when serializing to HTML (HtmlExtension).

Options

Configuration for syntax (TypeScript type).

Type

export type {Options} from 'micromark-extension-gfm-strikethrough'

See Options.

HtmlOptions

Configuration for HTML (TypeScript type).

Type

export type {HtmlOptions} from 'micromark-extension-gfm-footnote'

See HtmlOptions.

Bugs

For bugs present in GFM but not here, or other peculiarities that are supported, see each corresponding readme:

• autolink literal
• footnote
• strikethrough: n/a
• table
• tagfilter: n/a
• tasklists: n/a

Authoring

For recommendations on how to author GFM, see each corresponding readme:

• autolink literal
• footnote
• strikethrough
• table
• tagfilter: n/a
• tasklists

HTML

For info on what HTML features GFM relates to, see each corresponding readme:

• autolink literal
• footnote
• strikethrough
• table
• tagfilter
• tasklists

CSS

For info on how GitHub styles these features, see each corresponding readme:

• autolink literal
• footnote
• strikethrough
• table
• tagfilter: n/a
• tasklists

Syntax

For info on the syntax of these features, see each corresponding readme:

• autolink literal
• footnote
• strikethrough
• table
• tagfilter: n/a
• tasklists

Types

This package is fully typed with TypeScript. It exports the additional types HtmlOptions and Options.

Compatibility

Projects maintained by the unified collective are compatible with maintained versions of Node.js.

When we cut a new major release, we drop support for unmaintained versions of Node. This means we try to keep the current release line, micromark-extension-gfm@^3, compatible with Node.js 16.

This package works with micromark version 3 and later.

Security

This package is safe. Setting clobberPrefix = '' is dangerous, it opens you up to DOM clobbering. The labelTagName and labelAttributes options are unsafe when used with user content, they allow defining arbitrary HTML.

Contribute

See contributing.md in micromark/.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