remark-html

What is remark-html?

The remark-html package is a plugin for the remark processor that allows you to convert Markdown content into HTML. It is part of the unified collective, which provides a suite of tools for processing and transforming content.

What are remark-html's main functionalities?

Convert Markdown to HTML

This feature allows you to convert Markdown content into HTML. The code sample demonstrates how to use the remark processor with the remark-html plugin to transform a Markdown string into HTML.

const remark = require('remark');
const html = require('remark-html');

remark()
  .use(html)
  .process('# Hello World!', function (err, file) {
    if (err) throw err;
    console.log(String(file));
  });

Customizing HTML Output

This feature allows you to customize the HTML output. In this example, the `sanitize` option is set to `false`, which means that HTML tags in the Markdown content will not be sanitized and will be included in the output.

const remark = require('remark');
const html = require('remark-html');

remark()
  .use(html, { sanitize: false })
  .process('# Hello <em>World</em>!', function (err, file) {
    if (err) throw err;
    console.log(String(file));
  });

Other packages similar to remark-html

markdown-it

markdown-it is a fast and flexible Markdown parser that can be extended with plugins. It provides similar functionality to remark-html by converting Markdown to HTML, but it is known for its speed and extensibility.

marked

marked is a low-level Markdown compiler that allows for fast and efficient conversion of Markdown to HTML. It is similar to remark-html in its core functionality but is designed to be a simple and fast solution.

showdown

showdown is a bidirectional Markdown to HTML converter written in JavaScript. It offers similar functionality to remark-html but also supports converting HTML back to Markdown, providing more flexibility in content transformation.

README

remark-html

remark plugin to add support for serializing HTML.

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • unified().use(remarkHtml[, options])
  • Options
• Types
• Compatibility
• Security
• Related
• Contribute
• License

What is this?

This package is a unified (remark) plugin that compiles markdown to HTML.

When should I use this?

This plugin is useful when you want to turn markdown into HTML. It’s a shortcut for .use(remarkRehype).use(rehypeSanitize).use(rehypeStringify).

The reason that there are different ecosystems for markdown and HTML is that turning markdown into HTML is, while frequently needed, not the only purpose of markdown. Checking (linting) and formatting markdown are also common use cases for remark and markdown. There are several aspects of markdown that do not translate 1-to-1 to HTML. In some cases markdown contains more information than HTML: for example, there are several ways to add a link in markdown (as in, autolinks: <https://url>, resource links: [label](url), and reference links with definitions: [label][id] and [id]: url). In other cases HTML contains more information than markdown: there are many tags, which add new meaning (semantics), available in HTML that aren’t available in markdown. If there was just one AST, it would be quite hard to perform the tasks that several remark and rehype plugins currently do.

This plugin is useful when you want to quickly turn markdown into HTML. In most cases though, it’s recommended to use remark-rehype instead and finally use rehype-stringify to serialize HTML. The reason using both ecosystems instead of this plugin is recommended, is that there are many useful rehype plugins that you can then use. For example, you can minify HTML, format HTML, highlight code, add metadata, and a lot more.

Install

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

npm install remark-html

In Deno with esm.sh:

import remarkHtml from 'https://esm.sh/remark-html@16'

In browsers with esm.sh:

<script type="module">
  import remarkHtml from 'https://esm.sh/remark-html@16?bundle'
</script>

Use

Say we have the following file example.md:

# Pluto

**Pluto** (minor-planet designation: **134340 Pluto**) is a
[dwarf planet](https://en.wikipedia.org/wiki/Dwarf_planet) in the
[Kuiper belt](https://en.wikipedia.org/wiki/Kuiper_belt).

…and a module example.js:

import remarkHtml from 'remark-html'
import remarkParse from 'remark-parse'
import {read} from 'to-vfile'
import {unified} from 'unified'

const file = await unified()
  .use(remarkParse)
  .use(remarkHtml)
  .process(await read('example.md'))

console.log(String(file))

…then running node example.js yields:

<h1>Pluto</h1>
<p><strong>Pluto</strong> (minor-planet designation: <strong>134340 Pluto</strong>) is a
<a href="https://en.wikipedia.org/wiki/Dwarf_planet">dwarf planet</a> in the
<a href="https://en.wikipedia.org/wiki/Kuiper_belt">Kuiper belt</a>.</p>

API

This package exports no identifiers. The default export is remarkHtml.

unified().use(remarkHtml[, options])

Serialize markdown as HTML.

Parameters

• options (Options, optional) — configuration

Returns

Transform (Transformer).

Notes

Passing sanitize: false is dangerous. It allows arbitrary HTML and does not sanitize elements.

Options

Configuration (TypeScript type).

Fields

• handlers (Handlers from mdast-util-to-hast, optional) — how to turn mdast nodes into hast nodes
• sanitize (Schema from hast-util-sanitize or boolean, default: true) — sanitize the output, and how
• ...toHtmlOptions (Options from hast-util-to-html, optional) — other options are passed to hast-util-to-html

Types

This package is fully typed with TypeScript. It exports the additional type 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, remark-html@^16, compatible with Node.js 16.

This plugin works with unified version 6+ and remark version 15+.

Security

Use of remark-html is safe by default. Passing sanitize: false is unsafe and opens you up to cross-site scripting (XSS) attacks. A safe schema is used by default, but passing an unsafe schema is unsafe.

Related

• remark-rehype — turn markdown into HTML to support rehype
• rehype-sanitize — sanitize HTML

Contribute

See contributing.md in remarkjs/.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