# micromark-extension-gfm

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**[micromark][]** extension to support GitHub flavored markdown ([GFM][]).

## Contents

*   [What is this?](#what-is-this)
*   [When to use this](#when-to-use-this)
*   [Install](#install)
*   [Use](#use)
*   [API](#api)
    *   [`gfm(options?)`](#gfmoptions)
    *   [`gfmHtml(htmlOptions?)`](#gfmhtmlhtmloptions)
*   [Types](#types)
*   [Compatibility](#compatibility)
*   [Security](#security)
*   [Related](#related)
*   [Contribute](#contribute)
*   [License](#license)

## What is this?

This package is a micromark extension to add support for all GFM features:
autolink literals, footnotes, strikethrough, tables, tagfilter, and tasklists.

## When to use this

You probably should use this package if you use micromark and want to enable
GFM.
When working with syntax trees, you’d want to combine this package with
[`mdast-util-gfm`][mdast-util-gfm].

You can also use the underlying features separately:

*   [`micromark/micromark-extension-gfm-autolink-literal`][gfm-autolink-literal]
    — support GFM [autolink literals][]
*   [`micromark/micromark-extension-gfm-footnote`][gfm-footnote]
    — support GFM footnotes
*   [`micromark/micromark-extension-gfm-strikethrough`][gfm-strikethrough]
    — support GFM [strikethrough][]
*   [`micromark/micromark-extension-gfm-table`][gfm-table]
    — support GFM [tables][]
*   [`micromark/micromark-extension-gfm-tagfilter`][gfm-tagfilter]
    — support GFM [tagfilter][]
*   [`micromark/micromark-extension-gfm-task-list-item`][gfm-task-list-item]
    — support GFM [tasklists][]

These tools are all rather low-level.
In most cases, you’d instead want to use [`remark-gfm`][remark-gfm] with
[remark][].

## Install

This package is [ESM only][esm].
In Node.js (version 12.20+, 14.14+, or 16.0+), install with [npm][]:

```sh
npm install micromark-extension-gfm
```

In Deno with [Skypack][]:

```js
import {gfm, gfmHtml} from 'https://cdn.skypack.dev/micromark-extension-gfm@2?dts'
```

In browsers with [Skypack][]:

```html
<script type="module">
  import {gfm, gfmHtml} from 'https://cdn.skypack.dev/micromark-extension-gfm@2?min'
</script>
```

## Use

Say we have the following file `example.md`:

```markdown
# GFM

## 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

<plaintext>

## Tasklist

* [ ] to do
* [x] done
```

And our module `example.js` looks as follows:

```js
import fs from 'node:fs'
import {micromark} from 'micromark'
import {gfm, gfmHtml} from 'micromark-extension-gfm'

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

console.log(output)
```

Now, running `node example` yields:

```html
<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:contact@example.com">contact@example.com</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 following identifiers: `gfm`, `gfmHtml`.
There is no default export.

This extensions supports the endorsed [`development` condition][dev].
Run `node --conditions development module.js` to get instrumented dev code.
Without this condition, production code is loaded.

### `gfm(options?)`

A function that can be called to get an extension for micromark to parse GFM
(can be passed in `extensions`).

##### `options`

Configuration (optional).

###### `options.singleTilde`

Whether to support strikethrough with a single tilde (`boolean`, default:
`true`).
Single tildes work on github.com, but are technically prohibited by GFM.
Passed as [`singleTilde`][single-tilde] in
[`micromark-extension-gfm-strikethrough`][gfm-strikethrough].

### `gfmHtml(htmlOptions?)`

A function that can be called to get an extension to compile GFM to HTML (can be
passed in `htmlExtensions`).

##### `htmlOptions`

Configuration (optional).

###### `htmlOptions.clobberPrefix`

Prefix to use before the `id` attribute to prevent it from *clobbering*
attributes (`string`, default: `'user-content-'`).
Passed as [`clobberPrefix`][clobber-prefix] in
[`micromark-extension-gfm-footnote`][gfm-footnote].

###### `htmlOptions.label`

Label to use for the footnotes section (`string`, default: `'Footnotes'`).
Passed as [`label`][label] in
[`micromark-extension-gfm-footnote`][gfm-footnote].

###### `htmlOptions.backLabel`

Label to use from backreferences back to their footnote call (`string`, default:
`'Back to content'`).
Passed as [`backLabel`][backlabel] in
[`micromark-extension-gfm-footnote`][gfm-footnote].

## Types

This package is fully typed with [TypeScript][].
It exports additional `Options` and `HtmlOptions` types that model their
respective interfaces.

## Compatibility

This package is at least compatible with all maintained versions of Node.js.
As of now, that is Node.js 12.20+, 14.14+, and 16.0+.
It also works in Deno and modern browsers.

## Security

This package is safe by default.

## Related

*   [`syntax-tree/mdast-util-gfm`][mdast-util-gfm]
    — support GFM in mdast
*   [`remarkjs/remark-gfm`][remark-gfm]
    — support GFM in remark
*   [`micromark/micromark-extension-gfm-autolink-literal`][gfm-autolink-literal]
    — support GFM [autolink literals][]
*   [`micromark/micromark-extension-gfm-footnote`][gfm-footnote]
    — support GFM footnotes
*   [`micromark/micromark-extension-gfm-strikethrough`][gfm-strikethrough]
    — support GFM [strikethrough][]
*   [`micromark/micromark-extension-gfm-table`][gfm-table]
    — support GFM [tables][]
*   [`micromark/micromark-extension-gfm-tagfilter`][gfm-tagfilter]
    — support GFM [tagfilter][]
*   [`micromark/micromark-extension-gfm-task-list-item`][gfm-task-list-item]
    — support GFM [tasklists][]

## Contribute

See [`contributing.md` in `micromark/.github`][contributing] for ways to get
started.
See [`support.md`][support] for ways to get help.

This project has a [code of conduct][coc].
By interacting with this repository, organization, or community you agree to
abide by its terms.

## License

[MIT][license] © [Titus Wormer][author]

<!-- Definitions -->

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[downloads]: https://www.npmjs.com/package/micromark-extension-gfm

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[chat]: https://github.com/micromark/micromark/discussions

[npm]: https://docs.npmjs.com/cli/install

[skypack]: https://www.skypack.dev

[license]: license

[author]: https://wooorm.com

[contributing]: https://github.com/micromark/.github/blob/HEAD/contributing.md

[support]: https://github.com/micromark/.github/blob/HEAD/support.md

[coc]: https://github.com/micromark/.github/blob/HEAD/code-of-conduct.md

[esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c

[dev]: https://nodejs.org/api/packages.html#packages_resolving_user_conditions

[typescript]: https://www.typescriptlang.org

[micromark]: https://github.com/micromark/micromark

[remark]: https://github.com/remarkjs/remark

[remark-gfm]: https://github.com/remarkjs/remark-gfm

[gfm]: https://github.github.com/gfm/

[strikethrough]: https://github.github.com/gfm/#strikethrough-extension-

[tables]: https://github.github.com/gfm/#tables-extension-

[tasklists]: https://github.github.com/gfm/#task-list-items-extension-

[autolink literals]: https://github.github.com/gfm/#autolinks-extension-

[tagfilter]: https://github.github.com/gfm/#disallowed-raw-html-extension-

[single-tilde]: https://github.com/micromark/micromark-extension-gfm-strikethrough#optionssingletilde

[clobber-prefix]: https://github.com/micromark/micromark-extension-gfm-footnote#htmloptionsclobberprefix

[label]: https://github.com/micromark/micromark-extension-gfm-footnote#htmloptionslabel

[backlabel]: https://github.com/micromark/micromark-extension-gfm-footnote#htmloptionsbacklabel

[gfm-strikethrough]: https://github.com/micromark/micromark-extension-gfm-strikethrough

[gfm-autolink-literal]: https://github.com/micromark/micromark-extension-gfm-autolink-literal

[gfm-footnote]: https://github.com/micromark/micromark-extension-gfm-footnote

[gfm-table]: https://github.com/micromark/micromark-extension-gfm-table

[gfm-tagfilter]: https://github.com/micromark/micromark-extension-gfm-tagfilter

[gfm-task-list-item]: https://github.com/micromark/micromark-extension-gfm-task-list-item

[mdast-util-gfm]: https://github.com/syntax-tree/mdast-util-gfm