[Solved] Given this code snippet, what will be the output on the second request to /hello? import { Controller, Get, UseInterceptors } from '@nestjs/common';... | NestJS

NestJS - Interceptors

Given this code snippet, what will be the output on the second request to /hello?

import { Controller, Get, UseInterceptors } from '@nestjs/common';
import { CacheInterceptor } from '@nestjs/cache-manager';

@Controller()
export class HelloController {
  private count = 0;

  @UseInterceptors(CacheInterceptor)
  @Get('hello')
  getHello() {
    this.count++;
    return `Hello count: ${this.count}`;
  }
}

A"Hello count: 1" first request, "Hello count: 2" second request

BError because count is private

C"Hello count: 0" on both requests

D"Hello count: 1" on first and second request

Step-by-Step Solution

Solution:

Step 1: Understand CacheInterceptor behavior
CacheInterceptor caches the response of the first request and returns it for subsequent requests without calling the method again.
Step 2: Analyze the count variable increment
On the first request, count increments to 1 and returns "Hello count: 1". On the second request, the cached response is returned, so count does not increment again.
Final Answer:
"Hello count: 1" on first and second request -> Option D
Quick Check:
Cache returns cached response = B [OK]

Quick Trick: CacheInterceptor returns cached response, method not re-executed [OK]

Common Mistakes:

Assuming count increments on every request
Thinking private variables cause errors here
Ignoring caching effect on method execution

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Given this code snippet, what will be the output on the second request to /hello?

Step 1: Understand CacheInterceptor behavior

Step 2: Analyze the count variable increment

Final Answer:

Quick Check:

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