readme-upstream.md

Remark Math

Math Inline and Block supporting for Remark

What does Remark Math?

remark-math parses $ for inlineMath node and $$ for math node.

Also, you can transform the tex content of inlineMath and math nodes into html by rehype-katex or remark-html-katex.

Usages

There are two examples for server-side(examples/nodejs) and browser-side(examples/webpack, via webpack).

You can run the demo by npm run demo:nodejs and npm run demo:webpack.

Basic usages(Using rehype-katex, a little verbose but recommended)

Install dependencies

npm i -S remark remark-math remark-rehype rehype-katex rehype-stringify

const remark = require('remark')
const math = require('remark-math')
const remark2rehype = require('remark-rehype')
const katex = require('rehype-katex')
const stringify = require('rehype-stringify')

// Raw String => MDAST => HAST => transformed HAST => HTML
const processor = remark()
  .use(math)
  .use(remark2rehype)
  .use(katex)
  .use(stringify)

// https://en.wikipedia.org/wiki/Lift_(force)#Lift_coefficient
const rawString = `Lift($L$) can be determined by Lift Coeeficient ($C_L$) like the following equation.

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

const result = processor.processSync(rawString).toString()
/* result
<p>
  Lift(<span class="inlineMath"><span class="katex">...</span></span>) can be determined by Lift Coeeficient (<span class="inlineMath"><span class="katex">...</span></span>) like the following equation.
</p>
<div class="math">
  <span class="katex-display"><span class="katex">...</span></span>
</div>
*/

Another usages(Using remark-html-katex)

npm i -S remark remark-math remark-html-katex remark-html

const remark = require('remark')
const math = require('remark-math')
const katex = require('remark-html-katex') // Use remark-html-katex
const html = require('remark-html')

// Raw String => MDAST => transformed MDAST => HTML
const processor = remark()
  .use(math)
  .use(katex)
  .use(html)

Using only math inline(or math block)

You can access separated processors by remark-math/inline and remark-math/block

const remark = require('remark')
const remark2rehype = require('remark-rehype')
const katex = require('rehype-katex')
const stringify = require('rehype-stringify')

const mathInline = require('remark-math/inline')
// const mathBlock = require('remark-math/block')

// Parse only inline
const processor = remark()
  .use(mathInline)
  .use(remark2rehype)
  .use(katex)
  .use(stringify)

API

remark-math

remark-math does not handle any option.

rehype-katex and remark-html-katex

const katex = require('rehype-katex')

const processor = remark()
  .use(math)
  .use(remark2rehype)
  .use(katex, {
    throwOnError: false,
    errorColor: '#FF0000',
    inlineDoubleDisplay: false
  })
  .use(stringify)

options.throwOnError

Throw if a KaTeX parse error occurs. (default: false)

options.errorColor

As long as options.throwOnError is not true, ParseError message will be colored by options.errorColor. (default: #cc0000)

KaTeX#rendering-options

inlineMathDouble (EXPERIMENTAL: Use with caution)

options.inlineMathDouble of remark-math (EXPERIMENTAL)

Add inlineMathDouble class to inline $$ math. It will have two classes, inlineMath and inlineMathDouble (default: false)

options.inlineMathDoubleDisplay of rehype-katex (EXPERIMENTAL)

If an element has inlineMathDouble class, set displayMode of KaTeX true. (default: false)

Usage

This option, together with a CSS rule like .inlineMathDouble {display: block; text-align: center;} allows authors to have equations inside paragraphs on a separate line:

const unified = require('unified')
const parse = require('remark-parse')
const remark2rehype = require('remark-rehype')
const rehypeKatex = require('rehype-katex')
const stringify = require('rehype-stringify')

const processor = unified()
  .use(parse)
  .use(math, {
    inlineMathDouble: true
  })
  .use(remark2rehype)
  .use(rehypeKatex, {
    inlineMathDoubleDisplay: true
  })
  .use(stringify)

Specs

Escaped Dollars

Dollar signs can be escaped by back slash, \.

\$\alpha\$

Escaped dollars in math block/inline (Super factorial)

$\alpha\$$

$$
\beta\$
$$

Double dollars in inline

Some TeX packages and Markdown processors use double dollars, $$, as a inline token. Remark Math will parse it also properly.

$$\alpha$$

License

MIT © Junyoung Choi