README

remark

unified processor with support for parsing markdown input and serializing markdown as output.

What is this?
When should I use this?
Install
Use
API
- remark()
Examples
- Example: checking markdown
- Example: passing options to remark-stringify
Syntax
Syntax tree
Types
Compatibility
Security
Contribute
Sponsor
License

What is this?

This package is a unified processor with support for parsing markdown input and serializing markdown as output by using unified with remark-parse and remark-stringify.

unified is a project that transforms content with abstract syntax trees (ASTs). remark adds support for markdown to unified. mdast is the markdown AST that remark uses. Please see the monorepo readme for what the remark ecosystem is.

When should I use this?

You can use this package when you want to use unified, have markdown as input, and want markdown as output. This package is a shortcut for unified().use(remarkParse).use(remarkStringify). When the input isn’t markdown (meaning you don’t need remark-parse) or the output is not markdown (you don’t need remark-stringify), it’s recommended to use unified directly.

When you want to inspect and format markdown files in a project on the command line, you can use remark-cli.

Install

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

npm install remark

In Deno with Skypack:

import {remark} from 'https://cdn.skypack.dev/remark@14?dts'

In browsers with Skypack:

<script type="module">
  import {remark} from 'https://cdn.skypack.dev/remark@14?min'
</script>

Use

Say we have the following module example.js:

import {remark} from 'remark'
import remarkGfm from 'remark-gfm'
import remarkToc from 'remark-toc'

main()

async function main() {
  const file = await remark()
    .use(remarkGfm)
    .use(remarkToc)
    .process('# Hi\n\n## Table of contents\n\n## Hello\n\n*Some* ~more~ _things_.')

  console.error(String(file))
}

Running that with node example.js yields:

# Hi

## Table of contents

*   [Hello](#hello)

## Hello

*Some* ~~more~~ *things*.

API

This package exports the following identifier: remark. There is no default export.

`remark()`

Create a new (unfrozen) unified processor that already uses remark-parse and remark-stringify and you can add more plugins to. See unified for more information.

Examples

Example: checking markdown

The following example checks that markdown code style is consistent and follows some best practices:

import {reporter} from 'vfile-reporter'
import {remark} from 'remark'
import remarkPresetLintConsistent from 'remark-preset-lint-consistent'
import remarkPresetLintRecommended from 'remark-preset-lint-recommended'

main()

async function main() {
  const file = await remark()
    .use(remarkPresetLintConsistent)
    .use(remarkPresetLintRecommended)
    .process('1) Hello, _Jupiter_ and *Neptune*!')

  console.error(reporter(file))
}

Yields:

        1:1  warning  Missing newline character at end of file  final-newline              remark-lint
   1:1-1:35  warning  Marker style should be `.`                ordered-list-marker-style  remark-lint
        1:4  warning  Incorrect list-item indent: add 1 space   list-item-indent           remark-lint
  1:25-1:34  warning  Emphasis should use `_` as a marker       emphasis-marker            remark-lint

⚠ 4 warnings

Example: passing options to `remark-stringify`

When you use remark-stringify manually you can pass options to use. Because remark-stringify is already used in remark, that’s not possible. To define options for remark-stringify, you can instead pass options to data:

import {remark} from 'remark'

main()

async function main() {
  const file = await remark()
    .data('settings', {bullet: '*', setext: true, listItemIndent: 'one'})
    .process('# Moons of Neptune\n\n- Naiad\n- Thalassa\n- Despine\n- …')

  console.log(String(file))
}

Yields:

Moons of Neptune
================

* Naiad
* Thalassa
* Despine
* …

Syntax

Markdown is parsed and serialized according to CommonMark. Other plugins can add support for syntax extensions.

Syntax tree

The syntax tree format used in remark is mdast.

Types

This package is fully typed with TypeScript. There are no extra exported types.

Compatibility

Projects maintained by the unified collective are compatible with all maintained versions of Node.js. As of now, that is Node.js 12.20+, 14.14+, and 16.0+. Our projects sometimes work with older versions, but this is not guaranteed.

Security

As markdown can be turned into HTML and improper use of HTML can open you up to cross-site scripting (XSS) attacks, use of remark can be unsafe. When going to HTML, you will likely combine remark with rehype, in which case you should use rehype-sanitize.

Use of remark plugins could also open you up to other attacks. Carefully assess each plugin and the risks involved in using them.

For info on how to submit a report, see our security policy.

Contribute

See contributing.md in remarkjs/.github for ways to get started. See support.md for ways to get help. Join us in Discussions to chat with the community and contributors.

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