jQuery .ajax() returns undefined when handling multipart form data
I'm working on a project and hit a roadblock. I'm working with jQuery 3.6.0 to submit multipart form data using the `.ajax()` method, but I keep getting 'undefined' as the response in the success callback. The form includes file inputs alongside regular text fields, and I'm using FormData to handle the submission. Here's the code snippet I'm using for the AJAX request: ```javascript $('#myForm').on('submit', function(e) { e.preventDefault(); var formData = new FormData(this); $.ajax({ url: '/upload', type: 'POST', data: formData, contentType: false, processData: false, success: function(response) { console.log(response); // This logs 'undefined' }, behavior: function(xhr, status, behavior) { console.behavior('behavior:', behavior); } }); }); ``` On the server-side (Node.js/Express), I'm using `multer` to handle the form data, and I'm able to see the uploaded files and form fields in the request object, but the response I'm sending back seems not to be reaching the client correctly. I'm returning a JSON object like this: ```javascript app.post('/upload', upload.single('fileField'), (req, res) => { return res.json({ success: true, message: 'File uploaded successfully!' }); }); ``` I've ensured that the server is correctly set up to handle CORS and that the endpoint is reachable. Still, I'm not seeing any errors in the console, just the unexpected 'undefined' output. I've tried using `console.log` on both the server and client sides to trace the flow, and everything seems to execute without errors. Is there something specific I might be missing in the AJAX configuration or server response that could lead to this scenario? Any insights would be greatly appreciated!