MDX Plugins

Sometimes, you may want to extend or tweak your Markdown syntax. For example:

• How do I embed youtube videos using the image syntax (![](https://youtu.be/yKNxeF4KMsY))?
• How do I style links that are on their own lines differently, e.g., as a social card?
• How do I make every page start with a copyright notice?

And the answer is: create an MDX plugin! MDX has a built-in plugin system that can be used to customize how the Markdown files will be parsed and transformed to JSX. There are three typical use-cases of MDX plugins:

• Using existing remark plugins or rehype plugins;
• Creating remark/rehype plugins to transform the elements generated by existing MDX syntax;
• Creating remark/rehype plugins to introduce new syntaxes to MDX.

If you play with the MDX playground, you would notice that the MDX transpilation has two intermediate steps: Markdown AST (MDAST), and Hypertext AST (HAST), before arriving at the final JSX output. MDX plugins also come in two forms:

• Remark: processes the Markdown AST.
• Rehype: processes the Hypertext AST.

提示

Use plugins to introduce shorter syntax for the most commonly used JSX elements in your project. The admonition syntax that we offer is also generated by a Remark plugin, and you could do the same for your own use case.

Default plugins

Docusaurus injects some default Remark plugins during Markdown processing. These plugins would:

• Generate the table of contents;
• Add anchor links to each heading;
• Transform images and links to require() calls.
• … These are all typical use-cases of Remark plugins, which can also be a source of inspiration if you want to implement your own plugin.

Installing plugins

An MDX plugin is usually an npm package, so you install them like other npm packages using npm. Take the math plugins as an example.

npm

npm install --save remark-math@6 rehype-katex@7

Yarn

yarn add remark-math@6 rehype-katex@7

pnpm

pnpm add remark-math@6 rehype-katex@7

How are remark-math and rehype-katex different?

In case you are wondering how Remark and Rehype are different, here is a good example. remark-math operates on the Markdown AST, where it sees text like $...$, and all it does is transform that to the JSX <span class="math math-inline">...</span> without doing too much with the content. This decouples the extraction of math formulae from their rendering, which means you can swap $\KaTeX$ out with other math renderers, like MathJax (with rehype-mathjax), just by replacing the Rehype plugin.

Next, the rehype-katex operates on the Hypertext AST where everything has been converted to HTML-like tags already. It traverses all the elements with math class and uses $\KaTeX$ to parse and render the content to actual HTML.

注意

Many official Remark/Rehype plugins are ES Modules only, a JavaScript module system, which Docusaurus supports. We recommend using an ES Modules config file to make it easier to import such packages.

Next, import your plugins and add them to the plugin options through plugin or preset config in docusaurus.config.ts:

docusaurus.config.ts

import remarkMath from 'remark-math';
import rehypeKatex from 'rehype-katex';

export default {
  presets: [
    [
      '@docusaurus/preset-classic',
      {
        docs: {
          path: 'docs',
          remarkPlugins: [remarkMath],
          rehypePlugins: [rehypeKatex],
        },
      },
    ],
  ],
};