feat: Support LaTeX and AsciiMath via MathJax on stem.excalidraw.com

src/packages/extensions/ts/mathjax/index.ts

@@ -0,0 +1,32 @@
+import { useEffect } from "react";
+import { ExcalidrawImperativeAPI } from "../../../../types";
+import { addSubtypeMethods } from "../../../../subtypes";
+import { getMathSubtypeRecord } from "./types";
+import { prepareMathSubtype } from "./implementation";
+
+export const MathJaxExtension = "mathjax";
+
+// Extension authors: provide a hook like `useMyExtension` in `myextension/index`
+export const useMathJaxExtension = (api: ExcalidrawImperativeAPI | null) => {
+  const enabled = mathJaxExtensionLoadable;
+  useEffect(() => {
+    if (enabled && api) {
+      const prep = api.addSubtype(getMathSubtypeRecord(), prepareMathSubtype);
+      if (prep) {
+        addSubtypeMethods(getMathSubtypeRecord().subtype, prep.methods);
+      }
+    }
+  }, [enabled, api]);
+};
+
+// Extension authors: Use a variable like `myExtensionLoadable` to determine
+// whether or not to do anything in each of `useMyExtension` and `testMyExtension`.
+let mathJaxExtensionLoadable = false;
+
+export const getMathJaxExtensionLoadable = () => {
+  return mathJaxExtensionLoadable;
+};
+
+export const setMathJaxExtensionLoadable = (loadable: boolean) => {
+  mathJaxExtensionLoadable = loadable;
+};