diff --git a/src/App.tsx b/src/App.tsx
index 97f12ba..b093a44 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -1,6 +1,6 @@
 import React from 'react';
 
-function App() {
+function App() : JSX.Element {
   return (
     <div>
     </div>
diff --git a/src/index.tsx b/src/index.tsx
index ea7d317..9a4b410 100644
--- a/src/index.tsx
+++ b/src/index.tsx
@@ -1,8 +1,8 @@
+import App from './App';
 import React from 'react';
 import ReactDOM from 'react-dom/client';
-import App from './App';
 
-const root = ReactDOM.createRoot(
+const root : ReactDOM.Root = ReactDOM.createRoot(
   document.getElementById('root') as HTMLElement
 );
 
diff --git a/tsconfig.json b/tsconfig.json
index a273b0c..fdd47ce 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -6,7 +6,7 @@
       "dom.iterable",
       "esnext"
     ],
-    "allowJs": true,
+    "allowJs": false,
     "skipLibCheck": true,
     "esModuleInterop": true,
     "allowSyntheticDefaultImports": true,