Express JS Express Middleware 3

Question 1

Which middleware package is commonly used to parse cookie headers in Express?

Accepted Answer

cookie-parser

Answer

The cookie-parser middleware parses the Cookie header and populates req.cookies with key-value pairs.

Question 2

What is the purpose of the helmet package in an Express application?

Accepted Answer

Sets security-related HTTP response headers

Answer

helmet sets various HTTP headers to protect against common web vulnerabilities like XSS and clickjacking.

Question 3

Where should error-handling middleware be placed in an Express application?

Accepted Answer

After all other app.use() and route definitions

Answer

Error-handling middleware must be defined last so it can catch errors passed via next(err) from all prior middleware and routes.

Question 4

Which middleware is used to compress HTTP responses in Express?

Accepted Answer

compression

Answer

The compression middleware compresses response bodies using gzip or deflate before sending them to the client.

Question 5

What does next('router') do when called inside a Router middleware?

Accepted Answer

Skips the rest of the router's middleware and returns control to the parent app

Answer

next('router') bypasses the remaining handlers in the current router and returns control to the parent application.

Express JS Practice Test