Math Equations

Mathematical equations can be rendered using KaTeX.

Usage

Please read KaTeX documentation for more details.

Inline

Write inline math equations by wrapping LaTeX equations between $:

Let $f\colon[a,b]\to\R$ be Riemann integrable. Let $F\colon[a,b]\to\R$ be
$F(x)=\int_{a}^{x} f(t)\,dt$. Then $F$ is continuous, and at all $x$ such that
$f$ is continuous at $x$, $F$ is differentiable at $x$ with $F'(x)=f(x)$.

http://localhost:3000

Let $f\colon[a,b] \to \R$ be Riemann integrable. Let $F\colon[a,b]\to\R$ be $F(x)= \int_{a}^{x} f(t)\,dt$. Then $F$ is continuous, and at all $x$ such that $f$ is continuous at $x$, $F$ is differentiable at $x$ with $F'(x)=f(x)$.

Blocks

For equation block or display mode, use line breaks and $$:

$$
I = \int_0^{2\pi} \sin(x)\,dx
$$

http://localhost:3000

$$I = \int_0^{2\pi} \sin(x)\,dx$$

Configuration

To enable KaTeX, you need to install remark-math and rehype-katex plugins.

npm

npm install --save remark-math@3 rehype-katex@5 hast-util-is-element@1.1.0

Yarn

yarn add remark-math@3 rehype-katex@5 hast-util-is-element@1.1.0

caution

Use the exact same versions. The latest versions are incompatible with Docusaurus 2.

Import the plugins in docusaurus.config.js:

const math = require('remark-math');
const katex = require('rehype-katex');

Add them to your content plugin or preset options (usually @docusaurus/preset-classic docs options):

remarkPlugins: [math],
rehypePlugins: [katex],

Include the KaTeX CSS in your config under stylesheets:

stylesheets: [
  {
    href: 'https://cdn.jsdelivr.net/npm/katex@0.13.24/dist/katex.min.css',
    type: 'text/css',
    integrity:
      'sha384-odtC+0UGzzFL/6PNoE8rX/SPcQDXBJ+uRepguP4QkPCm2LBxH3FA3y+fKSiJ+AmM',
    crossorigin: 'anonymous',
  },
],

Overall the changes look like:

docusaurus.config.js

const math = require('remark-math');
const katex = require('rehype-katex');

module.exports = {
  title: 'Docusaurus',
  tagline: 'Build optimized websites quickly, focus on your content',
  presets: [
    [
      '@docusaurus/preset-classic',
      {
        docs: {
          path: 'docs',
          remarkPlugins: [math],
          rehypePlugins: [katex],
        },
      },
    ],
  ],
  stylesheets: [
    {
      href: 'https://cdn.jsdelivr.net/npm/katex@0.13.24/dist/katex.min.css',
      type: 'text/css',
      integrity:
        'sha384-odtC+0UGzzFL/6PNoE8rX/SPcQDXBJ+uRepguP4QkPCm2LBxH3FA3y+fKSiJ+AmM',
      crossorigin: 'anonymous',
    },
  ],
};

Self-hosting KaTeX assets

Loading stylesheets, fonts, and javascript libraries from CDN sources is a good practice for popular libraries and assets, since it reduces the amount of assets you have to host. In case you prefer to self-host the katex.min.css (along with required KaTeX fonts), you can download the latest version from KaTeX GitHub releases, extract and copy katex.min.css and fonts directory (only .woff2 font types should be enough) to your site's static directory, and in docusaurus.config.js, replace the stylesheet's href from the CDN url to your local path (say, /katex/katex.min.css).

docusaurus.config.js

module.exports = {
  stylesheets: [
    {
      href: '/katex/katex.min.css',
      type: 'text/css',
    },
  ],
};

Upgrading rehype-katex beyond recommended version

tip

Only use the latest version if you actually need the bleeding-edge features of $\KaTeX$. Most users should find the older versions work just as well.

The latest versions of rehype-katex (starting from v6.0.0) has moved to ES Modules, a new module system of JavaScript, which Docusaurus doesn't officially support yet. However, it is possible to import rehype-katex dynamically, using an async config creator. Docusaurus will call this creator function and wait for it to return the config object.

docusaurus.config.js

async function createConfig() {
  // ES Modules are imported with `import()` instead of `require()`, and are imported asynchronously
  const katex = (await import('rehype-katex')).default;
  return {
    // ...
  };
}

In this case, the overall configuration changes will look like:

docusaurus.config.js

const math = require('remark-math');

async function createConfig() {
  const katex = (await import('rehype-katex')).default;
  return {
    title: 'Docusaurus',
    tagline: 'Build optimized websites quickly, focus on your content',
    presets: [
      [
        '@docusaurus/preset-classic',
        {
          docs: {
            path: 'docs',
            remarkPlugins: [math],
            rehypePlugins: [katex],
          },
        },
      ],
    ],
    stylesheets: [
      {
        href: 'https://cdn.jsdelivr.net/npm/katex@0.15.2/dist/katex.min.css',
        type: 'text/css',
        integrity:
          'sha384-MlJdn/WNKDGXveldHDdyRP1R4CTHr3FeuDNfhsLPYrq2t0UBkUdK2jyTnXPEK1NQ',
        crossorigin: 'anonymous',
      },
    ],
  };
}

module.exports = createConfig;