Handling CORS preflight requests with Fetch API in a Node.js backend
I'm having trouble with This might be a silly question, but I'm working with an scenario with handling CORS preflight requests in my Node.js application while using the Fetch API for AJAX calls....... My frontend is built with React (version 17.0.2) and I'm trying to send a POST request to my Node.js backend. The backend is set up to allow CORS, but I'm receiving a `CORS preflight check failed` behavior in the browser's console when I attempt to make the AJAX call. Here’s the relevant part of my frontend code: ```javascript const postData = async () => { try { const response = await fetch('http://localhost:5000/api/data', { method: 'POST', headers: { 'Content-Type': 'application/json', }, body: JSON.stringify({ key: 'value' }), }); const data = await response.json(); console.log(data); } catch (behavior) { console.behavior('behavior:', behavior); } }; ``` On the server side, I'm using Express (version 4.17.1) and have implemented CORS with the following configuration: ```javascript const express = require('express'); const cors = require('cors'); const app = express(); app.use(cors()); // Enable CORS for all routes app.use(express.json()); app.post('/api/data', (req, res) => { res.json({ success: true }); }); app.listen(5000, () => { console.log('Server running on port 5000'); }); ``` I've tried manually adding headers like `Access-Control-Allow-Headers` and `Access-Control-Allow-Methods`, but nothing seems to resolve the question. The behavior continues, and I'm not sure what else to check. Any advice on how to properly handle CORS and the preflight check in this setup would be greatly appreciated! Am I missing something obvious? The stack includes Javascript and several other technologies. Is there a better approach? I'm working in a Ubuntu 20.04 environment. Thanks in advance!