feat: add math equation support in Tinymce (#233)

apps/backend/src/routes/katex.js

@@ -0,0 +1,24 @@
+const express = require('express');
+// https://ben.page/node-latex-to-html
+const katex = require('katex');
+
+const router = express.Router();
+
+// localhost:3002/katex
+router.get('/', async (req, res) => {
+  const original = req._parsedUrl.search;
+
+  const latexString = original.replace('?', '').replaceAll('+', '+').replaceAll('&space;', '');
+  console.log({ latexString });
+
+  const html = katex.renderToString(latexString, {
+    throwOnError: false,
+    output: 'mathml'
+  });
+
+  console.log({ html });
+
+  res.send(html);
+});
+
+module.exports = router;