Status codes and headers in NestJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of HTTP status codes in NestJS?

HTTP status codes tell the client if a request was successful or if there was an error. In NestJS, they help communicate the result of an API call clearly.

beginner

How do you set a custom HTTP status code in a NestJS controller?

Use the @HttpCode() decorator above the controller method to set a custom status code, for example, @HttpCode(201) sets the status to 201 Created.

beginner

What is the role of HTTP headers in NestJS responses?

HTTP headers carry extra information about the response, like content type or caching rules. In NestJS, you can set headers to control how clients handle the response.

intermediate

How can you set HTTP headers in a NestJS controller method?

You can inject the Response object from Express using @Res() and then use res.set() or res.header() to add headers before sending the response.

intermediate

What is the difference between using @Res() and returning a value directly in NestJS controllers regarding status codes and headers?

Using @Res() gives full control over the response, including headers and status codes, but you must manually send the response. Returning a value lets NestJS handle status codes and headers automatically based on decorators.

Which decorator sets the HTTP status code for a NestJS controller method?

A @SetStatus()

B @Status()

C @ResponseCode()

D @HttpCode()

The @HttpCode() decorator is used to set the HTTP status code for a controller method in NestJS.

How do you add a custom header to a response in NestJS?

A Use res.set() on the injected Response object

B Use @Header() decorator on the controller method

C Return an object with headers property

D NestJS sets headers automatically; you cannot add custom ones

You add custom headers by injecting the Response object with @Res() and calling res.set() or res.header() before sending the response.

What status code does NestJS return by default for a successful GET request?

A 201 Created

B 200 OK

C 204 No Content

D 400 Bad Request

By default, NestJS returns 200 OK for successful GET requests.

If you use @Res() in a controller method, what must you remember to do?

A Manually send the response using res.send() or res.json()

B Return the response object from the method

C Use @HttpCode() to set status code

D Nothing special; NestJS handles response automatically

When using @Res(), you must manually send the response with res.send() or res.json(), otherwise the client will not get a response.

Which header is commonly used to specify the type of content returned by a NestJS API?

A Accept-Encoding

B Authorization

C Content-Type

D Cache-Control

The Content-Type header tells the client what type of data is in the response, such as application/json.

Explain how to set both a custom status code and headers in a NestJS controller method.

Think about decorators and direct response manipulation.

Describe the difference between returning a value directly and using @Res() in NestJS controllers regarding response control.

Consider who controls the response sending.