# Changes done by the Luogu Dev Team

As we use slightly different LaTeX standards, we modified the parser a bit, especially the part that checks if the LaTeX `$`

delimeter is valid, to suit our standards.

# markdown-it-katex

Add Math to your Markdown

KaTeX is a faster alternative to MathJax. This plugin makes it easy to support in your markdown.

Need convincing?

- Check out the comparative benchmark: KaTeX vs MathJax

## Usage

Install markdown-it

```
npm install markdown-it
```

Install the plugin

```
npm install @iktakahiro/markdown-it-katex
```

Use it in your javascript

```
var md = require('markdown-it')(),
mk = require('@iktakahiro/markdown-it-katex');
md.use(mk);
// double backslash is required for javascript strings, but not html input
var result = md.render('# Math Rulez! \n $\\sqrt{3x-1}+(1+x)^2$');
```

Include the KaTeX stylesheet in your html:

```
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.9.0/katex.min.css">
```

If you're using the default markdown-it parser, I also recommend the github stylesheet:

```
<link rel="stylesheet" href="https://cdn.jsdelivr.net/github-markdown-css/2.2.1/github-markdown.css"/>
```

`KaTeX`

options can be supplied with the second argument to use.

```
md.use(mk, {"throwOnError" : false, "errorColor" : " #cc0000"});
```

## Examples

### Inline

Surround your LaTeX with a single `$`

on each side for inline rendering.

```
$\sqrt{3x-1}+(1+x)^2$
```

### Block

Use two (`$$`

) for block rendering. This mode uses bigger symbols and centers
the result.

```
$$\begin{array}{c}
\nabla \times \vec{\mathbf{B}} -\, \frac1c\, \frac{\partial\vec{\mathbf{E}}}{\partial t} &
= \frac{4\pi}{c}\vec{\mathbf{j}} \nabla \cdot \vec{\mathbf{E}} & = 4 \pi \rho \\
\nabla \times \vec{\mathbf{E}}\, +\, \frac1c\, \frac{\partial\vec{\mathbf{B}}}{\partial t} & = \vec{\mathbf{0}} \\
\nabla \cdot \vec{\mathbf{B}} & = 0
\end{array}$$
```

## Syntax

Math parsing in markdown is designed to agree with the conventions set by pandoc:

```
Anything between two $ characters will be treated as TeX math. The opening $ must
have a non-space character immediately to its right, while the closing $ must
have a non-space character immediately to its left, and must not be followed
immediately by a digit. Thus, $20,000 and $30,000 won’t parse as math. If for some
reason you need to enclose text in literal $ characters, backslash-escape them and
they won’t be treated as math delimiters.
```

## Math Syntax Support

KaTeX is based on TeX and LaTeX. Support for both is growing. Here's a list of currently supported functions: