rehype-katex
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!Chatchat-badgechatrehype plugin to render elements with a
language-math
class with
KaTeX.Contents
* [`unified().use(rehypeKatex[, options])`](#unifieduserehypekatex-options)
* [`Options`](#options)
What is this?
This package is a unified (rehype) plugin to render math. You can add classes to HTML elements, use fenced code in markdown, or combine withremark-math
remark-math for a $C$
syntax extension.When should I use this?
This project is useful as it renders math with KaTeX at compile time, which means that there is no client side JavaScript needed.A different plugin,
rehype-mathjax
rehype-mathjax, does the same but with
MathJax.Install
This package is ESM onlyesm. In Node.js (version 16+), install with npm:npm install rehype-katex
In Deno with
esm.sh
esmsh:import rehypeKatex from 'https://esm.sh/rehype-katex@7'
In browsers with
esm.sh
esmsh:<script type="module">
import rehypeKatex from 'https://esm.sh/rehype-katex@7?bundle'
</script>
Use
Say our documentinput.html
contains:<p>
Lift(<code class="language-math">L</code>) can be determined by Lift Coefficient
(<code class="language-math">C_L</code>) like the following equation.
</p>
<pre><code class="language-math">
L = \frac{1}{2} \rho v^2 S C_L
</code></pre>
…and our module
example.js
contains:import rehypeDocument from 'rehype-document'
import rehypeKatex from 'rehype-katex'
import rehypeParse from 'rehype-parse'
import rehypeStringify from 'rehype-stringify'
import {read, write} from 'to-vfile'
import {unified} from 'unified'
const file = await unified()
.use(rehypeParse, {fragment: true})
.use(rehypeDocument, {
// Get the latest one from: <https://katex.org/docs/browser>.
css: 'https://cdn.jsdelivr.net/npm/katex@0.16.8/dist/katex.min.css'
})
.use(rehypeKatex)
.use(rehypeStringify)
.process(await read('input.html'))
file.basename = 'output.html'
await write(file)
…then running
node example.js
creates an output.html
with:<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>input</title>
<meta content="width=device-width, initial-scale=1" name="viewport">
<link href="https://cdn.jsdelivr.net/npm/katex@0.16.8/dist/katex.min.css" rel="stylesheet">
</head>
<body>
<p>
Lift(<span class="katex"><!--…--></span>) can be determined by Lift Coefficient
(<span class="katex"><!--…--></span>) like the following equation.
</p>
<span class="katex-display"><!--…--></span>
</body>
</html>
…open
output.html
in a browser to see the rendered math.API
This package exports no identifiers. The default export isrehypeKatex
api-rehype-katex.unified().use(rehypeKatex[, options])
Render elements with a language-math
(or math-display
, math-inline
)
class with KaTeX.Parameters
options
(Options
api-options)
— configuration
Returns
Transform (Transformer
unified-transformer).Options
Configuration (TypeScript type).Type
import {KatexOptions} from 'katex'
type Options = Omit<KatexOptions, 'displayMode' | 'throwOnError'>
See Options on
katex.org
katex-options for more info.Markdown
This plugin supports the syntax extension enabled byremark-math
remark-math.
It also supports math generated by using fenced code:````markdown
C_L
````HTML
The content of any element with alanguage-math
, math-inline
, or
math-display
class is transformed.
The elements are replaced by what KaTeX renders.
Either a math-display
class or using <pre><code class="language-math">
will
result in “display” math: math that is a centered block on its own line.CSS
The HTML produced by KaTeX requires CSS to render correctly. You should usekatex.css
somewhere on the page where the math is shown to
style it properly.
At the time of writing, the last version is:<!-- Get the latest one from: https://katex.org/docs/browser -->
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.16.8/dist/katex.min.css">
Types
This package is fully typed with TypeScript. It exports the additional typeOptions
api-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,
rehype-katex@^7
,
compatible with Node.js 16.This plugin works with unified version 6+ and rehype version 4+.
Security
Assuming you trust KaTeX, usingrehype-katex
is safe.
A vulnerability in it could open you to a
cross-site scripting (XSS)wiki-xss attack.
Be wary of user input and use rehype-sanitize
rehype-sanitize.When you don’t trust user content but do trust KaTeX, run
rehype-katex
after rehype-sanitize
:import rehypeKatex from 'rehype-katex'
import rehypeSanitize, {defaultSchema} from 'rehype-sanitize'
import rehypeStringify from 'rehype-stringify'
import remarkMath from 'remark-math'
import remarkParse from 'remark-parse'
import remarkRehype from 'remark-rehype'
import {unified} from 'unified'
const file = await unified()
.use(remarkParse)
.use(remarkMath)
.use(remarkRehype)
.use(rehypeSanitize, {
...defaultSchema,
attributes: {
...defaultSchema.attributes,
// The `language-*` regex is allowed by default.
code: [['className', /^language-./, 'math-inline', 'math-display']]
}
})
.use(rehypeKatex)
.use(rehypeStringify)
.process('$C$')
console.log(String(file))
Related
— same but with MathJax
— highlight code blocks
— add links to headings
— sanitize HTML
— wrap a document around the tree
Contribute
Seecontributing.md
contributing in remarkjs/.github
health for ways
to get started.
See support.md
support for ways to get help.This project has a code of conductcoc. By interacting with this repository, organization, or community you agree to abide by its terms.