TypeError: Cannot read property 'name' of undefined || Problem with FileUpload

Question

I can't add a post, I think the problem is connected with fileupload.

Here is the error:

TypeError: Cannot read property 'name' of undefined
    at addPost (C:\Users\Web-Developer\Desktop\crud-app\routes\post.js:21:37)
    at Layer.handle [as handle_request] (C:\Users\Web-Developer\Desktop\crud-app\node_modules\express\lib\router\layer.js:95:5)
    at next (C:\Users\Web-Developer\Desktop\crud-app\node_modules\express\lib\router\route.js:137:13)
    at Route.dispatch (C:\Users\Web-Developer\Desktop\crud-app\node_modules\express\lib\router\route.js:112:3)
    at Layer.handle [as handle_request] (C:\Users\Web-Developer\Desktop\crud-app\node_modules\express\lib\router\layer.js:95:5)
    at C:\Users\Web-Developer\Desktop\crud-app\node_modules\express\lib\router\index.js:281:22
    at Function.process_params (C:\Users\Web-Developer\Desktop\crud-app\node_modules\express\lib\router\index.js:335:12)
    at next (C:\Users\Web-Developer\Desktop\crud-app\node_modules\express\lib\router\index.js:275:10)
    at C:\Users\Web-Developer\Desktop\crud-app\node_modules\express-fileupload\lib\processMultipart.js:140:9
    at processTicksAndRejections (internal/process/task_queues.js:97:5)

Here is my code :

addPost: (req, res) => {
        if (!req.files) {
            return res.status(400).send("No files were uploaded.");
        }

        let message = '';
        let title = req.body.title;
        let description = req.body.description;
        let category = req.body.category;
        let date = req.body.date;
        let main_image = req.files.main_image;
        let image_name = main_image.name;
        let fileExtension = main_image.mimetype.split('/')[1];
        image_name = title + '.' + fileExtension;

        let titleQuery = "SELECT * FROM `posts` WHERE title = '" + title + "'";

        db.query(titleQuery, (err, result) => {
            if (err) {
                return res.status(500).send(err);
            }
            if (result.length > 0) {
                message = 'Post already exists';
                res.render('add-player.ejs', {
                    message,
                    title: 'Welcome to BLOG'
                });
            } else {
                // check the filetype before uploading it
                if (main_image.mimetype === 'image/png' || main_image.mimetype === 'image/jpeg' || main_image.mimetype === 'image/gif') {
                    // upload the file to the /public/assets/img directory
                    main_image.mv(`public/assets/img/${image_name}`, (err ) => {
                        if (err) {
                            return res.status(500).send(err);
                        }
                        // send the post's details to the database
                        let query = "INSERT INTO `posts` (title, description, category, date, main_image) VALUES ('" +
                            title + "', '" + description + "', '" + category + "', '" + date + "', '" + image_name + "')";
                        db.query(query, (err, result) => {
                            if (err) {
                                return res.status(500).send(err);
                            }
                            res.redirect('/');
                        });
                    });
                } else {
                    message = "Invalid File format. Only 'gif', 'jpeg' and 'png' images are allowed.";
                    res.render('add-player.ejs', {
                        message,
                        title: 'Welcome to BLOG'
                    });
                }
            }
        });
    }