title: Handling errors in an express middleware module
body: <p>I'm creating a module, which is an express middleware. My question is, when it encounters some kind of error (for example an acl module that sees that the user has no access right to this content), what is the best practice, calling next() with an error, so the app using the module can handle it the way it chooses, or can I send a response and not even call next?</p>