Response handling in NestJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of response handling in NestJS?

Response handling in NestJS manages how the server sends data back to the client after processing a request. It ensures the client receives the right data, status codes, and headers.

beginner

How do you send a JSON response in a NestJS controller?

You return a JavaScript object or array from the controller method. NestJS automatically converts it to JSON and sends it with a 200 status code.

intermediate

What decorator can you use to set a custom HTTP status code in NestJS?

You use the @HttpCode() decorator above a controller method to set a custom HTTP status code for the response.

intermediate

How can you send a file as a response in NestJS?

You can inject the Response object from Express using @Res() and use its methods like res.sendFile() to send files directly.

advanced

What is the difference between returning data and using @Res() in NestJS controllers?

Returning data lets NestJS handle the response automatically (recommended). Using @Res() gives you full control but disables automatic response handling, so you must manage headers and status codes yourself.

In NestJS, what happens if you return an object from a controller method?

A NestJS ignores the return value.

B NestJS sends it as plain text.

C NestJS throws an error.

D NestJS sends it as a JSON response with status 200.

Returning an object from a controller method automatically sends it as JSON with HTTP status 200.

Which decorator sets a custom HTTP status code for a response in NestJS?

A @ResponseStatus()

B @StatusCode()

C @HttpCode()

D @SetStatus()

The @HttpCode() decorator sets a custom HTTP status code for the response.

What must you do if you use @Res() in a NestJS controller method?

A Return the response object.

B Manually send the response using res methods.

C Nothing, NestJS handles the response automatically.

D Use @HttpCode() to set status.

Using @Res() disables automatic response handling, so you must manually send the response.

How do you send a file in a NestJS controller?

A Use @Res() and call res.sendFile().

B Return the file path as a string.

C Use @HttpCode(201).

D Return a Buffer object.

Inject the response object with @Res() and use res.sendFile() to send files.

What is the recommended way to handle responses in NestJS?

A Return data and let NestJS handle the response automatically.

B Use raw Node.js response objects.

C Use console.log to send responses.

D Always use @Res() for full control.

Returning data lets NestJS handle serialization and status codes automatically, which is simpler and less error-prone.

Explain how NestJS handles response data when you return an object from a controller method.

Think about what NestJS does behind the scenes with returned data.

Describe the differences and trade-offs between returning data and using the @Res() decorator in NestJS controllers.

Consider ease of use versus control.