Express JS Express Request and Response

Question 1

Which property of the request object contains the parsed body of a POST request with JSON content?

Accepted Answer

req.body

Answer

After applying express.json() middleware, the parsed JSON body is available on req.body.

Question 2

How do you send a JSON response in Express?

Accepted Answer

res.json(data)

Answer

res.json() automatically sets Content-Type to application/json and serializes the given object.

Question 3

Which method sets the HTTP status code of a response in Express?

Accepted Answer

res.status(code)

Answer

res.status() sets the HTTP status code for the response and returns the response object for chaining.

Question 4

How do you retrieve the value of the 'Authorization' request header in Express?

Accepted Answer

req.get('Authorization') or req.headers['authorization']

Answer

req.get() retrieves a request header case-insensitively, or you can access req.headers directly using lowercase keys.

Question 5

What is the difference between res.send() and res.end() in Express?

Accepted Answer

res.send() sets headers and body; res.end() is lower-level and sends no body by default

Answer

res.send() sets Content-Type and Content-Length automatically; res.end() is a raw Node.js method with no automatic header handling.

Express JS Practice Test