feat: custom global latex macros (closes #1325)

docs/plugins/Latex.md

@@ -12,6 +12,7 @@ This plugin adds LaTeX support to Quartz. See [[features/Latex|Latex]] for more
 This plugin accepts the following configuration options:
 
 - `renderEngine`: the engine to use to render LaTeX equations. Can be `"katex"` for [KaTeX](https://katex.org/) or `"mathjax"` for [MathJax](https://www.mathjax.org/) [SVG rendering](https://docs.mathjax.org/en/latest/output/svg.html). Defaults to KaTeX.
+- `customMacros`: custom macros for all LaTeX blocks. It takes the form of a key-value pair where the key is a new command name and the value is the expansion of the macro. For example: `{"\\R": "\\mathbb{R}"}`
 
 ## API
 

quartz/plugins/transformers/latex.ts

@@ -5,10 +5,16 @@ import { QuartzTransformerPlugin } from "../types"
 
 interface Options {
   renderEngine: "katex" | "mathjax"
+  customMacros: MacroType
+}
+
+interface MacroType {
+  [key: string]: string
 }
 
 export const Latex: QuartzTransformerPlugin<Options> = (opts?: Options) => {
   const engine = opts?.renderEngine ?? "katex"
+  const macros = opts?.customMacros ?? {}
   return {
     name: "Latex",
     markdownPlugins() {
@@ -16,9 +22,9 @@ export const Latex: QuartzTransformerPlugin<Options> = (opts?: Options) => {
     },
     htmlPlugins() {
       if (engine === "katex") {
-        return [[rehypeKatex, { output: "html" }]]
+        return [[rehypeKatex, { output: "html", macros }]]
       } else {
-        return [rehypeMathjax]
+        return [[rehypeMathjax, { macros }]]
       }
     },
     externalResources() {