Format response for validation errors

src/Application.ts

@@ -71,8 +71,25 @@ export default abstract class Application {
             }
 
             if (err instanceof ValidationBag) {
+                res.format({
+                    json: () => {
+                        res.status(401);
+                        res.json({
+                            status: 'error',
+                            code: 401,
+                            message: 'Invalid form data',
+                            messages: err.getMessages(),
+                        });
+                    },
+                    text: () => {
+                        res.status(401);
+                        res.send('Error: ' + err.getMessages())
+                    },
+                    html: () => {
                         req.flash('validation', err.getMessages());
                         res.redirectBack();
+                    },
+                });
                 return;
             }