managed to convert back to typescript by updating @types/react and @types/react-dom using specific version

app/mark/page.jsx

@@ -1,37 +0,0 @@
-import { unified } from 'unified';
-import remarkGfm from "remark-gfm";
-import remarkParse from "remark-parse";
-import remarkRehype from "remark-rehype";
-import rehypeSanitize from "rehype-sanitize";
-import rehypeHighlight from "rehype-highlight";
-import rehypeReact from "rehype-react";
-import * as prod from 'react/jsx-runtime';
-
-import { readFile } from 'node:fs/promises';
-
-async function markPostString() {
-    let path = ""
-    if ('DUMMY_HTML_DIR' in process.env && typeof process.env.DUMMY_HTML_DIR === "string") {
-        path = process.env.DUMMY_HTML_DIR + "test1.md";
-    }
-    return await readFile(path, "utf-8")
-}
-
-
-export default async function Mark() {
-    let content = await markPostString();
-    let result = unified()
-        .use(remarkParse)
-        .use(remarkGfm)
-        .use(remarkRehype)
-        .use(rehypeSanitize)
-        .use(rehypeHighlight)
-        .use(rehypeReact, {
-            Fragment: prod.Fragment,
-            jsx: prod.jsx,
-            jsxs: prod.jsxs,
-        })
-        .processSync(content)
-
-    return result.result;
-}

app/mark/page.tsx

@@ -0,0 +1,27 @@
+import { unified } from 'unified';
+import remarkGfm from 'remark-gfm';
+import remarkParse from 'remark-parse';
+import remarkRehype from 'remark-rehype';
+import rehypeSanitize from 'rehype-sanitize';
+import rehypeHighlight from 'rehype-highlight';
+import rehypeReact, { Options as RehypeReactOptions } from 'rehype-react';
+import { Fragment, jsx, jsxs } from 'react/jsx-runtime';
+import { MarkPostString } from '@/components/dummyPost';
+
+export default async function Mark() {
+    let content = await MarkPostString();
+    let result = await unified()
+        .use(remarkParse)
+        .use(remarkGfm)
+        .use(remarkRehype)
+        .use(rehypeHighlight)
+        .use(rehypeSanitize)
+        .use(rehypeReact, {
+            Fragment: Fragment,
+            jsx: jsx,
+            jsxs: jsxs
+        } as RehypeReactOptions)
+        .process(content);
+
+    return result.result;
+}