try backend js

js/app.js

@@ -0,0 +1,11 @@
+const express = require('express');
+const app = express();
+const port = 3000;
+
+app.get('/', (req, res) => {
+    res.send('Hello from Node.js and Express!');
+});
+
+app.listen(port, () => {
+    console.log(`Example app listening at http://localhost:${port}`);
+});