Why middleware processes requests before handlers in NestJS - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to apply middleware that logs requests before reaching the handler.

NestJS

app.use([1]);

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

AerrorHandler

BhandleRequest

CresponseMiddleware

DloggerMiddleware

Attempts:

3 left

💡 Hint

Common Mistakes

Using the handler function instead of middleware.

Placing response middleware before request logging.

The middleware function loggerMiddleware processes requests before handlers to log details.

2fill in blank

medium

Complete the middleware function to call the next handler in the chain.

NestJS

function logger(req, res, [1]) {
  console.log('Request received');
  [1]();
}

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

Ahandle

Bprocess

Cnext

Dcontinue

Attempts:

3 left

💡 Hint

Common Mistakes

Not calling the next function, causing the request to hang.

Using incorrect parameter names.

The next function passes control to the next middleware or handler.

3fill in blank

hard

Fix the error in the middleware to ensure it processes requests before handlers.

NestJS

function authMiddleware(req, res, next) {
  if (!req.user) {
    res.status(401).send('Unauthorized');
  } else {
    [1]();
  }
}

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

Anext

Bhandle

Cprocess

Dcontinue

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to call next() after checks.

Calling a wrong function name.

Calling next() passes control to the next middleware or handler after authentication check.

4fill in blank

hard

Fill both blanks to create middleware that modifies request data before handler.

NestJS

function modifyMiddleware(req, res, [1]) {
  req.customData = 'data';
  [2]();
}

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

Anext

Bhandle

Cprocess

Dcontinue

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for the parameter and call.

Not calling next() after modification.

The next function is used both as parameter and called to continue processing.

5fill in blank

hard

Fill all three blanks to create middleware that logs, modifies, and passes request to handler.

NestJS

function combinedMiddleware(req, res, [1]) {
  console.log('Start');
  req.modified = true;
  [2]();
  console.log([3]);
}

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

Anext

Bhandle

C'End'

Dcontinue

Attempts:

3 left

💡 Hint

Common Mistakes

Not calling next() before logging 'End'.

Using wrong variable names.

The middleware uses next to continue and logs 'End' after calling it.