remark-math

remark plugin to support math ($C_L$).

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • unified().use(remarkMath[, options])
  • Options
• Authoring
• HTML
• CSS
• Syntax
• Syntax tree
• Types
• Compatibility
• Security
• Related
• Contribute
• License

What is this?

This package is a unified (remark) plugin to add support for math syntax. You can use this to add support for parsing and serializing this syntax extension.

As there is no spec for math in markdown, this extension follows how code (fenced and text) works in Commonmark, but uses dollars ($).

When should I use this?

This project is useful when you want to support math in markdown. Extending markdown with a syntax extension makes the markdown less portable. LaTeX equations are also quite hard. But this mechanism works well when you want authors, that have some LaTeX experience, to be able to embed rich diagrams of math in scientific text.

If you just want to turn markdown into HTML (with maybe a few extensions such as math), we recommend micromark with micromark-extension-math instead. If you don’t use plugins and want to access the syntax tree, you can use mdast-util-from-markdown with mdast-util-math.

This plugins adds fields on nodes so that the plugin responsible for turning markdown (mdast) into HTML (hast), remark-rehype, will turn text math (inline) into <code class="language-math math-inline">…</code> and flow math (block) into <pre><code class="language-math math-display">…</code></pre>.

Install

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

npm install remark-math

In Deno with esm.sh:

import remarkMath from 'https://esm.sh/remark-math@6'

In browsers with esm.sh:

<script type="module">
  import remarkMath from 'https://esm.sh/remark-math@6?bundle'
</script>

Use

Say our document example.md contains:

Lift($$L$$) can be determined by Lift Coefficient ($$C_L$$) like the following
equation.

$$
L = \frac{1}{2} \rho v^2 S C_L
$$

…and our module example.js contains:

import rehypeKatex from 'rehype-katex'
import rehypeStringify from 'rehype-stringify'
import remarkMath from 'remark-math'
import remarkParse from 'remark-parse'
import remarkRehype from 'remark-rehype'
import {read} from 'to-vfile'
import {unified} from 'unified'

const file = await unified()
  .use(remarkParse)
  .use(remarkMath)
  .use(remarkRehype)
  .use(rehypeKatex)
  .use(rehypeStringify)
  .process(await read('example.md'))

console.log(String(file))

…then running node example.js yields:

<p>Lift(<code class="language-math math-inline"><span class="katex">…</span></code>) like the following
equation.</p>
<pre><code class="language-math math-display"><span class="katex-display"><span class="katex">…</span></span></code></pre>

API

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

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

Add support for math.

Parameters

• options (Options, optional) — configuration

Returns

Nothing (undefined).

Options

Configuration (TypeScript type).

Fields

• singleDollarTextMath (boolean, default: true) — whether to support text math (inline) with a single dollar. Single dollars work in Pandoc and many other places, but often interfere with “normal” dollars in text. If you turn this off, you can still use two or more dollars for text math.

Authoring

When authoring markdown with math, keep in mind that math doesn’t work in most places. Notably, GitHub currently has a really weird crappy client-side regex-based thing. But on your own (math-heavy?) site it can be great!

Instead of a syntax extension to markdown, you can also use fenced code with an info string of math:

```math
L = \frac{1}{2} \rho v^2 S C_L
```

HTML

This plugin integrates with remark-rehype. When markdown (mdast) is turned into HTML (hast) the math nodes are turned into <code class="language-math math-inline">…</code> and <pre><code class="language-math math-display">…</code></pre> elements.

CSS

This package does not relate to CSS. You can choose to render the math with KaTeX, MathJax, or something else, which might need CSS.

Syntax

See Syntax in micromark-extension-math.

Syntax tree

See Syntax tree in mdast-util-math.

Types

This package is fully typed with TypeScript. It exports the additional type Options.

If you’re working with the syntax tree, you can register the new node types with @types/mdast by adding a reference:

// Register math nodes in mdast:
/// <reference types="mdast-util-math" />

import {visit} from 'unist-util-visit'

function myRemarkPlugin() {
  /**
   * @param {import('mdast').Root} tree
   *   Tree.
   * @returns {undefined}
   *   Nothing.
   */
  return function (tree) {
    visit(tree, function (node) {
      console.log(node) // `node` can now be one of the math nodes.
    })
  }
}

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-math@^6, compatible with Node.js 16.

This plugin works with unified version 6+ and remark version 14+. The previous major (version 4) worked with remark 13.

Security

Use of remark-math does not involve rehype (hast) or user content so there are no openings for cross-site scripting (XSS) attacks.

Related

• remark-gfm — support GFM (autolink literals, footnotes, strikethrough, tables, tasklists)
• remark-frontmatter — support frontmatter (YAML, TOML, and more)
• remark-directive — support directives
• remark-mdx — support MDX (ESM, JSX, expressions)

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 © Junyoung Choi