Controller pattern for route handlers in Express - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the Controller pattern in Express route handlers?

It is a way to organize code by separating route logic into controller functions. Controllers handle requests and responses, keeping routes clean and focused.

beginner

Why use controllers instead of writing all logic inside routes?

Controllers make code easier to read, test, and maintain by separating concerns. Routes just direct traffic, controllers do the work.

beginner

How do you define a controller function in Express?

A controller is a function that takes (req, res) parameters and handles the request, like sending a response or calling next().

beginner

Example: What does this controller do?
<pre>const getUser = (req, res) => { res.send('User info'); };</pre>

It sends a simple text response 'User info' when called. This controller handles a request by replying with user information.

beginner

How do you connect a controller to a route in Express?

You import or define the controller function and pass it as the second argument to the route method, like app.get('/path', controllerFunction).

What is the main role of a controller in Express?

A Handle the logic for requests and responses

B Define the URL paths for routes

C Manage database connections

D Serve static files

Controllers handle the logic for processing requests and sending responses.

Where should you put the code that sends a response to the client?

A In the middleware before the route

B Inside the route definition only

C Inside the controller function

D In the server setup file

Controllers are responsible for sending responses to keep routes clean.

How do you use a controller in an Express route?

A Pass the controller function as the route handler

B Call the controller inside the route handler manually

C Controllers are not used with routes

D Controllers replace the Express app

You pass the controller function directly as the route handler.

Which of these is a benefit of using controllers?

A Automatically creates routes

B Makes the server run faster

C Handles user authentication

D Improves code organization and readability

Controllers help organize code and make it easier to read and maintain.

What parameters does a typical Express controller function receive?

A app and router

B req and res

C next and error

D url and method

Controllers receive the request (req) and response (res) objects.

Explain how the Controller pattern helps organize Express route handlers.

Think about how splitting tasks makes code easier to manage.

Describe the steps to create and use a controller function in an Express app.

Focus on function creation and connecting it to routes.