Response methods and status codes in Node.js - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the HTTP status code sent by this Express response?

Consider this Express.js code snippet. What status code will the client receive?

Node.js

app.get('/test', (req, res) => {
  res.status(201).send('Created');
});

A 404

B 201

C 200

D 500

💡 Hint

Look at the status method argument.

The res.status(201) sets the HTTP status code to 201, which means 'Created'.

❓ component_behavior

intermediate

What will the response body be for this Express handler?

Given this Express route handler, what will the client see in the response body?

Node.js

app.get('/hello', (req, res) => {
  res.status(200).json({ message: 'Hello World' });
});

A undefined

B Hello World

C {"msg":"Hello World"}

D {"message":"Hello World"}

💡 Hint

Check the method used to send the response.

res.json sends a JSON string of the object, so the client receives {"message":"Hello World"}.

📝 Syntax

advanced

Which option correctly sends a 404 status with a plain text message?

Choose the correct Express.js code to send a 404 status with 'Not Found' text.

A res.send(404, 'Not Found');

B res.sendStatus(404, 'Not Found');

C res.status(404).send('Not Found');

D res.status(404).json('Not Found');

💡 Hint

Check the correct usage of res.status and res.send methods.

Option C correctly sets status 404 and sends plain text. Option C is deprecated syntax. Option C is invalid because sendStatus only takes status code. Option C sends JSON string, not plain text.

🔧 Debug

advanced

Why does this Express handler cause an error?

Identify the error in this Express route handler code.

Node.js

app.get('/error', (req, res) => {
  res.sendStatus(200).send('OK');
});

A res.sendStatus ends the response; calling send after causes an error.

B sendStatus requires two arguments; missing second argument causes error.

C res.sendStatus is not a function; typo in method name.

D send method cannot be chained after status method.

💡 Hint

Check what res.sendStatus returns and if chaining is allowed.

res.sendStatus sends the status and ends the response. Calling send after it causes an error because response is already finished.

🧠 Conceptual

expert

Which status code best fits this scenario in an Express API?

You have an API endpoint that successfully processes a request but does not return any content. Which HTTP status code should you use?

A 204 No Content

B 200 OK

C 202 Accepted

D 404 Not Found

💡 Hint

Think about status codes that indicate success but no response body.

204 means success with no content returned. 200 usually includes content. 202 means accepted but processing not complete. 404 means resource not found.