markdownitkatex
Add KaTeX rendering to your Markdown
Usage
$ npm install @traptitech/markdownitkatex
Including KaTeX CSS is needed.
Options

katex
: You can change KaTeX version by passing the instance. 
blockClass
: Class added to KaTeX block.  Any KaTeX Options
md.use(mk, {"blockClass": "mathblock", "errorColor" : " #cc0000"});
Examples
Inline
Surround your LaTeX with a single $
on each side for inline rendering.
$\sqrt{3x1}+(1+x)^2$
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 nonspace character immediately to its right, while the closing $ must
have a nonspace 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, backslashescape 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: