Context

When I set up this blog to have support for \(\LaTeX\) support, I was guilty of not really understanding what was going on. I basically only knew that GitHub’s default math engine was MathJax, and that if I wanted to use \(\KaTeX\) I was gonna have to write a script that parsed the intermediate representation by getting rid of the script tags of type math/tex.

Recently kramdown got updated and the output for MathJax changed and the intermediate representation changed, the math/tex tags are no longer there. Which for me, it means that \(\LaTeX\) support was broken.

How to Fix KaTeX After the Kramdown Update

I Google’d how to get around this new update and found this blog entry. The idea of rendering \(\TeX\) code server side was exciting and felt more robust. However, that did not end up working. I figured this time I would learn how exactly how GitHub pages work when it comes to additional Gems needed. And turns out, I learned quite a bit.

Basically, GitHub pages is limited when it comes to using additional Gems (which are needed for sever-side rendering), and not only that, specifically, GitHub pages limits its math engine to only mathjax, in fact, they override whatever setting you choose. They force it to be mathjax. So server-side rendering is out.

The Fix

The only option is going back to client-side rendering. Luckily, \(\KaTeX\) has our backs with the autorender extension.

You basically just let mathjax process your markdown files with \(\TeX\) code in it. The intermediate representation rendered by mathjax is compatible with the aforementioned extension. Javascript and \(\KaTeX\) take care of the rest by simply using the following:

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<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.12.0/dist/katex.min.css" integrity="sha384-AfEj0r4/OFrOo5t7NnNe46zW/tFgW6x/bCJG8FqQCEo3+Aro6EYUG4+cU+KJWu/X" crossorigin="anonymous">
<script defer src="https://cdn.jsdelivr.net/npm/katex@0.12.0/dist/katex.min.js" integrity="sha384-g7c+Jr9ZivxKLnZTDUhnkOnsh30B4H0rpLUpJ4jAIKs4fnJI+sEnkvrMWph2EDg4" crossorigin="anonymous"></script>
<script defer src="https://cdn.jsdelivr.net/npm/katex@0.12.0/dist/contrib/auto-render.min.js" integrity="sha384-mll67QQFJfxn0IYznZYonOWZ644AWYC+Pt2cHqMaRhXVrursRwvLnLaebdGIlYNa" crossorigin="anonymous"
    onload="renderMathInElement(document.body);"></script>

You can obviously choose when renderMathInElement is run. You can even choose not to add the code above whenever a post on your Jekyll blog doesn’t have math/formulas in it.

Additionally, you can write out the code yourself and not let mathjax process it for you.

Remember, your _config.yml file should not change the math_engine field.