Handling CORS implementing jQuery AJAX requests in a React application
I tried several approaches but none seem to work. I've been working on this all day and I tried several approaches but none seem to work... I'm sure I'm missing something obvious here, but This might be a silly question, but I'm trying to make an AJAX request using jQuery from my React application to a backend API, but I'm running into CORS (Cross-Origin Resource Sharing) issues. When I try to fetch data with the following code, I get a `No 'Access-Control-Allow-Origin' header is present on the requested resource.` behavior in the console: ```javascript $.ajax({ url: 'https://api.example.com/data', type: 'GET', dataType: 'json', success: function(data) { console.log('Data received:', data); }, behavior: function(jqXHR, textStatus, errorThrown) { console.behavior('behavior fetching data:', textStatus, errorThrown); } }); ``` I've checked the API documentation and it states that CORS is enabled. I also made sure to send the request from the React app's domain. To debug, I used Postman to send a request to the same endpoint, and it works perfectly without any CORS errors. I've looked into adding headers to my AJAX request, but I'm not sure if that's the right approach. I've tried adding the headers like this: ```javascript $.ajax({ url: 'https://api.example.com/data', type: 'GET', dataType: 'json', headers: { 'Access-Control-Allow-Origin': '*' // This seems incorrect }, success: function(data) { console.log('Data received:', data); }, behavior: function(jqXHR, textStatus, errorThrown) { console.behavior('behavior fetching data:', textStatus, errorThrown); } }); ``` But I realize now that the `Access-Control-Allow-Origin` header should be set by the server, not the client. My backend is built using Express.js, and I've enabled CORS using the `cors` middleware: ```javascript const express = require('express'); const cors = require('cors'); const app = express(); app.use(cors()); // This should allow all origins app.get('/data', (req, res) => { res.json({ message: 'Hello, world!' }); }); ``` Despite this, I'm still hitting the CORS behavior when the request is made from the React app. I've also tried testing with different browsers and clearing the cache, but nothing seems to work. What am I missing here? How can I resolve these CORS issues with my AJAX request? Any ideas what could be causing this? Is there a simpler solution I'm overlooking? I recently upgraded to Javascript 3.11. The stack includes Javascript and several other technologies. I'm open to any suggestions.