NestJS Communication & Stakeholder Relations 3

Question 1

Which NestJS feature allows you to intercept and transform outgoing responses before they reach the client?

Accepted Answer

Interceptors

Answer

Interceptors wrap method execution and can transform the response stream using RxJS operators.

Question 2

A product manager requests that all API errors follow a consistent JSON structure. What NestJS mechanism enforces this globally?

Accepted Answer

Global exception filter

Answer

A global exception filter catches all unhandled exceptions and serializes them into a uniform error response.

Question 3

In NestJS event-driven communication, what does @EventPattern() differ from @MessagePattern() in?

Accepted Answer

@EventPattern() handles fire-and-forget events; @MessagePattern() handles request-response

Answer

@EventPattern() handles one-way event emission while @MessagePattern() follows the request-response pattern and returns data.

Question 4

Which class from @nestjs/swagger should you use to document the expected request body shape?

Accepted Answer

@ApiBody()

Answer

@ApiBody() annotates the controller method to describe the expected body schema in Swagger.

Question 5

A frontend team complains about CORS errors when calling your NestJS API. What is the simplest fix?

Accepted Answer

Call app.enableCors() in main.ts

Answer

app.enableCors() enables Cross-Origin Resource Sharing in NestJS with sensible defaults or configurable options.

NestJS Practice Test