# remark [![Build][build-badge]][build] [![Coverage][coverage-badge]][coverage] [![Downloads][downloads-badge]][downloads] [![Size][size-badge]][size] [![Sponsors][sponsors-badge]][collective] [![Backers][backers-badge]][collective] [![Chat][chat-badge]][chat] **[unified][]** processor with support for parsing from markdown and serializing to markdown. ## Contents * [What is this?](#what-is-this) * [When should I use this?](#when-should-i-use-this) * [Install](#install) * [Use](#use) * [API](#api) * [`remark()`](#remark-1) * [Examples](#examples) * [Example: checking markdown](#example-checking-markdown) * [Example: passing options to `remark-stringify`](#example-passing-options-to-remark-stringify) * [Syntax](#syntax) * [Syntax tree](#syntax-tree) * [Types](#types) * [Compatibility](#compatibility) * [Security](#security) * [Contribute](#contribute) * [Sponsor](#sponsor) * [License](#license) ## What is this? This package is a [unified][] processor with support for parsing markdown as input and serializing markdown as output by using unified with [`remark-parse`][remark-parse] and [`remark-stringify`][remark-stringify]. See [the monorepo readme][remark] for info on 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`][remark-cli]. ## Install This package is [ESM only][esm]. In Node.js (version 16+), install with [npm][]: ```sh npm install remark ``` In Deno with [`esm.sh`][esmsh]: ```js import {remark} from 'https://esm.sh/remark@15' ``` In browsers with [`esm.sh`][esmsh]: ```html <script type="module"> import {remark} from 'https://esm.sh/remark@15?bundle' </script> ``` ## Use Say we have the following module `example.js`: ```js import {remark} from 'remark' import remarkToc from 'remark-toc' const doc = ` # Pluto Pluto is a dwarf planet in the Kuiper belt. ## Contents ## History ### Discovery In the 1840s, Urbain Le Verrier used Newtonian mechanics to predict the position of… ### Name and symbol The name Pluto is for the Roman god of the underworld, from a Greek epithet for Hades… ### Planet X disproved Once Pluto was found, its faintness and lack of a viewable disc cast doubt… ## Orbit Pluto's orbital period is about 248 years… ` const file = await remark() .use(remarkToc, {heading: 'contents', tight: true}) .process(doc) console.error(String(file)) ``` …running that with `node example.js` yields: ```markdown # Pluto Pluto is a dwarf planet in the Kuiper belt. ## Contents * [History](#history) * [Discovery](#discovery) * [Name and symbol](#name-and-symbol) * [Planet X disproved](#planet-x-disproved) * [Orbit](#orbit) ## History ### Discovery In the 1840s, Urbain Le Verrier used Newtonian mechanics to predict the position of… ### Name and symbol The name Pluto is for the Roman god of the underworld, from a Greek epithet for Hades… ### Planet X disproved Once Pluto was found, its faintness and lack of a viewable disc cast doubt… ## Orbit Pluto's orbital period is about 248 years… ``` ## API This package exports the identifier [`remark`][api-remark]. There is no default export. ### `remark()` Create a new unified processor that already uses [`remark-parse`][remark-parse] and [`remark-stringify`][remark-stringify]. You can add more plugins with `use`. See [`unified`][unified] for more information. ## Examples ### Example: checking markdown The following example checks that markdown code style is consistent and follows some best practices: ```js import {remark} from 'remark' import remarkPresetLintConsistent from 'remark-preset-lint-consistent' import remarkPresetLintRecommended from 'remark-preset-lint-recommended' import {reporter} from 'vfile-reporter' const file = await remark() .use(remarkPresetLintConsistent) .use(remarkPresetLintRecommended) .process('1) Hello, _Jupiter_ and *Neptune*!') console.error(reporter(file)) ``` Yields: ```txt 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`: ```js import {remark} from 'remark' const doc = ` # Moons of Neptune 1. Naiad 2. Thalassa 3. Despine 4. … ` const file = await remark() .data('settings', { bulletOrdered: ')', incrementListMarker: false, setext: true }) .process(doc) console.log(String(file)) ``` Yields: ```markdown Moons of Neptune ================ 1) Naiad 1) Thalassa 1) Despine 1) … ``` ## Syntax Markdown is parsed and serialized according to CommonMark. Other plugins can add support for syntax extensions. ## Syntax tree The syntax tree used in remark is [mdast][]. ## Types This package is fully typed with [TypeScript][]. There are no extra exported types. It also registers `Settings` with `unified`. If you’re passing options with `.data('settings', …)`, make sure to import this package somewhere in your types, as that registers the fields. ```js /// <reference types="remark" /> import {unified} from 'unified' // @ts-expect-error: `thisDoesNotExist` is not a valid option. unified().data('settings', {thisDoesNotExist: false}) ``` ## 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, `remark@^15`, compatible with Node.js 16. ## Security As markdown can be turned into HTML and improper use of HTML can open you up to [cross-site scripting (XSS)][xss] attacks, use of remark can be unsafe. When going to HTML, you will combine remark with **[rehype][]**, in which case you should use [`rehype-sanitize`][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][security]. ## Contribute See [`contributing.md`][contributing] in [`remarkjs/.github`][health] for ways to get started. See [`support.md`][support] for ways to get help. Join us in [Discussions][chat] to chat with the community and contributors. This project has a [code of conduct][coc]. By interacting with this repository, organization, or community you agree to abide by its terms. ## Sponsor Support this effort and give back by sponsoring on [OpenCollective][collective]! <table> <tr valign="middle"> <td width="20%" align="center" rowspan="2" colspan="2"> <a href="https://vercel.com">Vercel</a><br><br> <a href="https://vercel.com"><img src="https://avatars1.githubusercontent.com/u/14985020?s=256&v=4" width="128"></a> </td> <td width="20%" align="center" rowspan="2" colspan="2"> <a href="https://motif.land">Motif</a><br><br> <a href="https://motif.land"><img src="https://avatars1.githubusercontent.com/u/74457950?s=256&v=4" width="128"></a> </td> <td width="20%" align="center" rowspan="2" colspan="2"> <a href="https://www.hashicorp.com">HashiCorp</a><br><br> <a href="https://www.hashicorp.com"><img src="https://avatars1.githubusercontent.com/u/761456?s=256&v=4" width="128"></a> </td> <td width="20%" align="center" rowspan="2" colspan="2"> <a href="https://www.gitbook.com">GitBook</a><br><br> <a href="https://www.gitbook.com"><img src="https://avatars1.githubusercontent.com/u/7111340?s=256&v=4" width="128"></a> </td> <td width="20%" align="center" rowspan="2" colspan="2"> <a href="https://www.gatsbyjs.org">Gatsby</a><br><br> <a href="https://www.gatsbyjs.org"><img src="https://avatars1.githubusercontent.com/u/12551863?s=256&v=4" width="128"></a> </td> </tr> <tr valign="middle"> </tr> <tr valign="middle"> <td width="20%" align="center" rowspan="2" colspan="2"> <a href="https://www.netlify.com">Netlify</a><br><br> <!--OC has a sharper image--> <a href="https://www.netlify.com"><img src="https://images.opencollective.com/netlify/4087de2/logo/256.png" width="128"></a> </td> <td width="10%" align="center"> <a href="https://www.coinbase.com">Coinbase</a><br><br> <a href="https://www.coinbase.com"><img src="https://avatars1.githubusercontent.com/u/1885080?s=256&v=4" width="64"></a> </td> <td width="10%" align="center"> <a href="https://themeisle.com">ThemeIsle</a><br><br> <a href="https://themeisle.com"><img src="https://avatars1.githubusercontent.com/u/58979018?s=128&v=4" width="64"></a> </td> <td width="10%" align="center"> <a href="https://expo.io">Expo</a><br><br> <a href="https://expo.io"><img src="https://avatars1.githubusercontent.com/u/12504344?s=128&v=4" width="64"></a> </td> <td width="10%" align="center"> <a href="https://boostnote.io">Boost Note</a><br><br> <a href="https://boostnote.io"><img src="https://images.opencollective.com/boosthub/6318083/logo/128.png" width="64"></a> </td> <td width="10%" align="center"> <a href="https://markdown.space">Markdown Space</a><br><br> <a href="https://markdown.space"><img src="https://images.opencollective.com/markdown-space/e1038ed/logo/128.png" width="64"></a> </td> <td width="10%" align="center"> <a href="https://www.holloway.com">Holloway</a><br><br> <a href="https://www.holloway.com"><img src="https://avatars1.githubusercontent.com/u/35904294?s=128&v=4" width="64"></a> </td> <td width="10%"></td> <td width="10%"></td> </tr> <tr valign="middle"> <td width="100%" align="center" colspan="8"> <br> <a href="https://opencollective.com/unified"><strong>You?</strong></a> <br><br> </td> </tr> </table> ## License [MIT][license] © [Titus Wormer][author] <!-- Definitions --> [build-badge]: https://github.com/remarkjs/remark/workflows/main/badge.svg [build]: https://github.com/remarkjs/remark/actions [coverage-badge]: https://img.shields.io/codecov/c/github/remarkjs/remark.svg [coverage]: https://codecov.io/github/remarkjs/remark [downloads-badge]: https://img.shields.io/npm/dm/remark.svg [downloads]: https://www.npmjs.com/package/remark [size-badge]: https://img.shields.io/bundlejs/size/remark [size]: https://bundlejs.com/?q=remark [sponsors-badge]: https://opencollective.com/unified/sponsors/badge.svg [backers-badge]: https://opencollective.com/unified/backers/badge.svg [collective]: https://opencollective.com/unified [chat-badge]: https://img.shields.io/badge/chat-discussions-success.svg [chat]: https://github.com/remarkjs/remark/discussions [security]: https://github.com/remarkjs/.github/blob/main/security.md [health]: https://github.com/remarkjs/.github [contributing]: https://github.com/remarkjs/.github/blob/main/contributing.md [support]: https://github.com/remarkjs/.github/blob/main/support.md [coc]: https://github.com/remarkjs/.github/blob/main/code-of-conduct.md [license]: https://github.com/remarkjs/remark/blob/main/license [author]: https://wooorm.com [npm]: https://docs.npmjs.com/cli/install [esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c [esmsh]: https://esm.sh [mdast]: https://github.com/syntax-tree/mdast [rehype]: https://github.com/rehypejs/rehype [rehype-sanitize]: https://github.com/rehypejs/rehype-sanitize [remark]: https://github.com/remarkjs/remark [remark-parse]: ../remark-parse [remark-stringify]: ../remark-stringify [remark-cli]: ../remark-cli [typescript]: https://www.typescriptlang.org [unified]: https://github.com/unifiedjs/unified [xss]: https://en.wikipedia.org/wiki/Cross-site_scripting [api-remark]: #remark-1