404 Not Found handler in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a 404 handler middleware in Express.

Express

app.use(function(req, res, [1]) {
  res.status(404).send('Page not found');
});

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

Anext

Berror

Crequest

Dresponse

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'error' instead of 'next' as the third parameter.

Using 'request' or 'response' instead of the next function.

The third parameter in Express middleware is next, which passes control to the next middleware.

2fill in blank

medium

Complete the code to set the 404 status code before sending the response.

Express

app.use(function(req, res, next) {
  res.[1](404).send('Not Found');
});

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

AsetStatus

Bstatus

Ccode

DsendStatus

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'code' or 'setStatus' which are not Express methods.

Using 'sendStatus' which sends the status and ends the response immediately.

The status method sets the HTTP status code for the response.

3fill in blank

hard

Fix the error in the 404 handler to correctly handle unmatched routes.

Express

app.use(function(req, res, next) {
  res.status(404).[1]('Sorry, page not found');
});

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

Asend

Bwrite

Cjson

Dend

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'write' without ending the response causes hanging requests.

Using 'end' without sending content results in empty response.

Using 'json' sends JSON, not plain text.

The send method sends the response body and ends the response properly.

4fill in blank

hard

Fill both blanks to create a 404 handler that renders a 'notfound' view with status 404.

Express

app.use(function(req, res, next) {
  res.[1](404);
  res.[2]('notfound');
});

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

Astatus

Bsend

Crender

Djson

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'send' instead of 'render' to display a view.

Using 'json' which sends JSON instead of rendering a view.

First set the status with status, then render the view with render.

5fill in blank

hard

Fill all three blanks to create a 404 handler that logs the URL, sets status 404, and sends a message.

Express

app.use(function(req, res, next) {
  console.log('404 at: ' + [1]);
  res.[2](404);
  res.[3]('Page not found');
});

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

Areq.url

Bstatus

Csend

Dreq.path

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'req.path' instead of 'req.url' logs only the path, not query string.

Using 'sendStatus' instead of separate 'status' and 'send' calls.

Forgetting to set status before sending response.

Use req.url to log the full URL, status to set the status, and send to send the response.