Functional middleware in NestJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a functional middleware that logs the request method.

NestJS

export function loggerMiddleware(req, res, next) {
  console.log(req.[1]);
  next();
}

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

Amethod

Burl

Cbody

Dheaders

Attempts:

3 left

💡 Hint

Common Mistakes

Using req.url instead of req.method

Forgetting to call next() to continue middleware chain

The method property of the request object contains the HTTP method (GET, POST, etc.). Logging it shows which type of request was made.

2fill in blank

medium

Complete the code to apply the functional middleware globally in a NestJS app.

NestJS

import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';
import { loggerMiddleware } from './logger.middleware';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  app.[1](loggerMiddleware);
  await app.listen(3000);
}
bootstrap();

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

AuseGlobalGuards

Buse

CuseGlobalInterceptors

DuseGlobalFilters

Attempts:

3 left

💡 Hint

Common Mistakes

Using useGlobalGuards instead of use

Not importing the middleware function correctly

The use method is used to apply functional middleware globally in NestJS.

3fill in blank

hard

Fix the error in the functional middleware to correctly handle asynchronous operations.

NestJS

export async function asyncLoggerMiddleware(req, res, [1]) {
  await new Promise(resolve => setTimeout(resolve, 100));
  console.log('Async log:', req.method);
  next();
}

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

Anext

Bdone

Ccallback

Dhandle

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong parameter name for the third argument

Not calling next() after async code

The third parameter in middleware functions is conventionally called next. Calling next() continues the request cycle.

4fill in blank

hard

Fill both blanks to create a functional middleware that adds a custom header and calls next.

NestJS

export function customHeaderMiddleware(req, res, [1]) {
  res.setHeader('[2]', 'NestJS');
  next();
}

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

Anext

Bdone

CX-Custom-Header

DContent-Type

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong parameter name instead of next

Setting standard headers instead of custom ones

The third parameter is next to continue the middleware chain. The header X-Custom-Header is a common custom header name.

5fill in blank

hard

Fill all three blanks to create a functional middleware that logs the URL, sets a header, and calls next.

NestJS

export function fullMiddleware(req, res, [1]) {
  console.log('URL:', req.[2]);
  res.setHeader('[3]', 'Active');
  next();
}

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

Anext

Burl

CX-Status

Dmethod

Attempts:

3 left

💡 Hint

Common Mistakes

Using req.method instead of req.url for logging URL

Forgetting to call next()

The third parameter is next. The request URL is in req.url. The custom header X-Status is set to indicate status.