roadmap/quartz/plugins/transformers/latex.ts

import remarkMath from "remark-math"
import rehypeKatex from "rehype-katex"
import rehypeMathjax from "rehype-mathjax/svg.js"
import { QuartzTransformerPlugin } from "../types"

interface Options {
  renderEngine: "katex" | "mathjax"
}

export const Latex: QuartzTransformerPlugin<Options> = (opts?: Options) => {
  const engine = opts?.renderEngine ?? "katex"
  return {
    name: "Latex",
    markdownPlugins() {
      return [remarkMath]
    },
    htmlPlugins() {
      return [engine === "katex" ? [rehypeKatex, { output: "html" }] : [rehypeMathjax]]
    },
    externalResources() {
      return engine === "katex"
        ? {
            css: [
              // base css
              "https://cdn.jsdelivr.net/npm/katex@0.16.0/dist/katex.min.css",
            ],
            js: [
              {
                // fix copy behaviour: https://github.com/KaTeX/KaTeX/blob/main/contrib/copy-tex/README.md
                src: "https://cdn.jsdelivr.net/npm/katex@0.16.7/dist/contrib/copy-tex.min.js",
                loadTime: "afterDOMReady",
                contentType: "external",
              },
            ],
          }
        : {}
    },
  }
}