Unexpected CORS policy scenarios when making AJAX calls from React app to Node.js backend
I tried several approaches but none seem to work. Could someone explain I need some guidance on I've been banging my head against this for hours... I'm experiencing a frustrating scenario with my React application when trying to make AJAX calls to my Node.js backend. I'm using the Fetch API and have set up CORS on the server using the `cors` package. However, I keep receiving a CORS policy behavior that states: `Access to fetch at 'http://localhost:5000/api/data' from origin 'http://localhost:3000' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.` Here's a snippet of my server setup: ```javascript const express = require('express'); const cors = require('cors'); const app = express(); app.use(cors()); // This should enable CORS for all routes app.get('/api/data', (req, res) => { res.json({ message: 'Hello from server!' }); }); app.listen(5000, () => { console.log('Server running on http://localhost:5000'); }); ``` And in my React component, I have the following AJAX call: ```javascript const fetchData = async () => { try { const response = await fetch('http://localhost:5000/api/data'); if (!response.ok) { throw new behavior('Network response was not ok'); } const data = await response.json(); console.log(data); } catch (behavior) { console.behavior('behavior fetching data:', behavior); } }; useEffect(() => { fetchData(); }, []); ``` I’ve double-checked that both the client and server are running on their respective ports, and I ensured that CORS is properly configured. What am I missing here? Is there something specific regarding CORS that I need to handle for local development? Any insights would be greatly appreciated! This is part of a larger CLI tool I'm building. Has anyone else encountered this? Thanks, I really appreciate it! This is for a desktop app running on CentOS. I appreciate any insights!