remark-math-inline

A remark plugin for inline math using clean, unambiguous :math[...] syntax.

Why?

The standard $...$ syntax for inline math has problems:
- Ambiguity — $ conflicts with currency notation
- Poor parsing — Single $ delimiters are hard to parse reliably
- Tooling issues — Many Markdown parsers don't handle $ well

This plugin provides a cleaner alternative using explicit, directive-style syntax.

Install

``bash
npm install remark-math-inline
`

Usage

`javascript
import { unified } from 'unified'
import remarkParse from 'remark-parse'
import remarkMathInline from 'remark-math-inline'
import remarkRehype from 'remark-rehype'
import rehypeKatex from 'rehype-katex'
import rehypeStringify from 'rehype-stringify'

const html = await unified()
.use(remarkParse)
.use(remarkMathInline)
.use(remarkRehype)
.use(rehypeKatex)
.use(rehypeStringify)
.process('The formula :math[E = mc^2] is famous.')

console.log(String(html))
`

$3

`markdown
Inline math: :math[E = mc^2]

LaTeX commands work: :math[\alpha + \beta = \gamma]

Nested brackets are balanced: :math[f(x) = [a, b]]
`

$3

For display-mode math, use fenced code blocks with math language:

``markdown
`math
\int_0^1 x^2 dx = \frac{1}{3}
`
``

This works out of the box with rehype-katex — no additional plugin needed.

Escaping

- \] → literal ] (doesn't close the math)
- \\ → literal \
- Other backslash sequences are preserved as-is (e.g., \alpha stays \alpha)

AST Node

The plugin creates inlineMath nodes compatible with rehype-katex:

`typescript
interface InlineMath {
type: 'inlineMath'
value: string
data: {
hName: 'code'
hProperties: { className: ['language-math', 'math-inline'] }
hChildren: [{ type: 'text', value: string }]
}
}
`

Adjacency

:math[...] must not be preceded by a word character. For adjacency without spaces, use parentheses:

`markdown
mass(:math[m])
mass:math[m]
`

Use with remark-directive

If you use both remark-math-inline and remark-directive, the plugin registered last takes precedence for :math[...] syntax.

`javascript
// Math wins:
unified()
.use(remarkDirective)
.use(remarkMathInline) // registered last

// Directive wins:
unified()
.use(remarkMathInline)
.use(remarkDirective) // registered last
``

License

MIT