Cache interceptor in NestJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the CacheInterceptor from NestJS.

NestJS

import { [1] } from '@nestjs/common';

Drag options to blanks, or click blank then click option'

AController

BCacheModule

CHttpException

DCacheInterceptor

Attempts:

3 left

💡 Hint

Common Mistakes

Importing CacheModule instead of CacheInterceptor

Using unrelated imports like Controller or HttpException

The CacheInterceptor is imported from @nestjs/common to enable caching behavior in controllers or routes.

2fill in blank

medium

Complete the code to apply the CacheInterceptor globally using app.useGlobalInterceptors.

NestJS

app.[1](new CacheInterceptor());

Drag options to blanks, or click blank then click option'

AuseGlobalGuards

BuseGlobalFilters

CuseGlobalInterceptors

DuseGlobalPipes

Attempts:

3 left

💡 Hint

Common Mistakes

Using useGlobalGuards or useGlobalFilters which are for other purposes

Forgetting to instantiate CacheInterceptor with new

To apply caching globally, you use useGlobalInterceptors with an instance of CacheInterceptor.

3fill in blank

hard

Fix the error in the code to enable caching on a controller method using the CacheInterceptor.

NestJS

@UseInterceptors([1])
@Get('data')
getData() {
  return { message: 'Hello' };
}

Drag options to blanks, or click blank then click option'

ALogger

BCacheInterceptor

CHttpException

DCacheModule

Attempts:

3 left

💡 Hint

Common Mistakes

Using CacheModule instead of CacheInterceptor in the decorator

Using unrelated classes like Logger or HttpException

The @UseInterceptors decorator requires the CacheInterceptor to enable caching on the method.

4fill in blank

hard

Fill both blanks to configure the CacheModule with a TTL of 10 seconds.

NestJS

imports: [CacheModule.[1]({ ttl: [2] })]

Drag options to blanks, or click blank then click option'

Aregister

B10

C5

DforRoot

Attempts:

3 left

💡 Hint

Common Mistakes

Using forRoot instead of register for CacheModule

Setting TTL to 5 instead of 10

The CacheModule is configured with register method and a TTL (time to live) of 10 seconds.

5fill in blank

hard

Fill both blanks to create a custom cache interceptor class that extends CacheInterceptor and overrides trackBy method to cache only GET requests.

NestJS

export class CustomCacheInterceptor extends CacheInterceptor {
  trackBy(context: ExecutionContext): string | undefined {
    const request = context.switchToHttp().getRequest();
    if (request.method !== [1]) {
      return undefined;
    }
    return super.[2](context);
  }
}

Drag options to blanks, or click blank then click option'

A'POST'

BtrackBy

C'GET'

Dintercept

Attempts:

3 left

💡 Hint

Common Mistakes

Checking for 'POST' instead of 'GET'

Calling super.intercept instead of super.trackBy

The custom interceptor checks if the HTTP method is 'GET' to cache only GET requests. It overrides the trackBy method to customize cache key generation.