Project: micromark/micromark-extension-gfm

Package: micromark-extension-gfm@2.0.1

  1. Dependents: 0
  2. micromark extension to support GFM (GitHub Flavored Markdown)
  1. unified 181
  2. markdown 154
  3. micromark 37
  4. gfm 21
  5. micromark-extension 17
  6. table 13
  7. github 10
  8. strikethrough 6
  9. autolink 6
  10. footnote 6
  11. tasklist 3
  12. tagfilter 3


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micromark extensions to support GitHub flavored markdown (GFM).


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:

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.


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'


Say our document example.md contains:


## Autolink literals

www.example.com, https://example.com, and contact@example.com.

## Footnote

A note[^1]

[^1]: Big note.

## Strikethrough

~one~ or ~~two~~ tildes.

## Table

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

## Tag filter


## 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()]


…now running node example.js yields:

<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:contact@example.com">contact@example.com</a>.</p>
<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>
<p><del>one</del> or <del>two</del> tildes.</p>
<th align="left">b</th>
<th align="right">c</th>
<th align="center">d</th>
<h2>Tag filter</h2>
<li><input type="checkbox" disabled="" /> to do</li>
<li><input type="checkbox" disabled="" checked="" /> done</li>
<section data-footnotes="" class="footnotes"><h2 id="footnote-label" class="sr-only">Footnotes</h2>
<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>


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.


Create an extension for micromark to enable GFM syntax.


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


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


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


Configuration for syntax (TypeScript type).

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

See Options.


Configuration for HTML (TypeScript type).

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

See HtmlOptions.


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


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


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


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


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


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


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.


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.


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.


MIT © Titus Wormer