Controller decorator in NestJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the @Controller decorator in NestJS?

The <code>@Controller</code> decorator marks a class as a controller that can handle incoming HTTP requests and send responses. It groups related request handlers under a common route prefix.

beginner

How do you specify a route prefix using the @Controller decorator?

You pass a string to @Controller('prefix'). This prefix is added before all routes defined in the controller's methods.

beginner

Can a NestJS controller class have multiple route handlers? How?

Yes. Inside a controller class, you define multiple methods decorated with HTTP method decorators like @Get(), @Post(), etc. Each method handles a different route or HTTP verb.

beginner

What happens if you use @Controller() without any prefix string?

The controller will handle routes starting from the root path /. Its methods define the full route paths.

intermediate

How does NestJS use the @Controller decorator internally?

NestJS uses <code>@Controller</code> to register the class as a controller in its routing system. It reads the decorator metadata to map HTTP requests to the controller's methods.

What does the @Controller('users') decorator do?

A Imports the 'users' module

B Sets the route prefix to '/users' for all routes in the controller

C Creates a database table called 'users'

D Defines a service named 'users'

The string inside @Controller() sets the route prefix for all routes in that controller.

Which decorator is used inside a controller to handle GET requests?

A @Get()

B @Post()

C @Put()

D @Delete()

@Get() marks a method to handle HTTP GET requests.

If a controller has @Controller() with no prefix, what is the base route?

A /

B /controller

C /api

D /home

No prefix means the base route is the root path /.

Can a single NestJS controller handle multiple HTTP methods?

A Only if you use multiple <code>@Controller</code> decorators

B No, one controller handles only one HTTP method

C Yes, by defining multiple methods with different HTTP decorators

D Only if you extend another controller

A controller can have many methods each decorated with different HTTP method decorators.

What is the main role of the @Controller decorator in NestJS?

A To define a database schema

B To configure the server port

C To create a middleware

D To register a class as a route handler

@Controller registers the class as a handler for HTTP routes.

Explain how the @Controller decorator works in NestJS and how it helps organize routes.

Think about how a controller groups related web routes under one roof.

Describe how you would create a NestJS controller that handles GET requests at '/products' and POST requests at '/products'.

Focus on the decorator usage for the class and methods.