Centralized error handling in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a basic Express error handler middleware.

Node.js

app.use(function(err, req, res, [1]) {
  res.status(500).send('Something broke!');
});

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

Anext

Berror

Cresponse

Drequest

Attempts:

3 left

💡 Hint

Common Mistakes

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

Missing the fourth parameter entirely.

The error handler middleware in Express requires four parameters: err, req, res, and next. The 'next' parameter is used to pass control to the next middleware.

2fill in blank

medium

Complete the code to forward an error to the centralized error handler.

Node.js

app.get('/', (req, res, [1]) => {
  const err = new Error('Oops!');
  [1](err);
});

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

Anext

Berror

Chandle

Dsend

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'error' or 'handle' instead of 'next'.

Not calling any function to forward the error.

In Express, calling 'next' with an error object forwards the error to the centralized error handler middleware.

3fill in blank

hard

Fix the error in the centralized error handler to send JSON response.

Node.js

app.use((err, req, res, next) => {
  res.status(500).[1]({ error: err.message });
});

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

AsendFile

BsendText

Cjson

Drender

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'sendText' or 'render' which are not valid methods for JSON response.

Forgetting to send the error message in JSON format.

To send a JSON response in Express, use the 'json' method on the response object.

4fill in blank

hard

Fill both blanks to create a middleware that catches 404 errors and forwards them to the error handler.

Node.js

app.use((req, res, [1]) => {
  const err = new Error('Not Found');
  err.status = 404;
  [2](err);
});

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

Anext

Berror

Dsend

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'error' or 'send' instead of 'next'.

Not forwarding the error to the next middleware.

The middleware uses 'next' to pass control and forward the error to the centralized error handler.

5fill in blank

hard

Fill all three blanks to create a centralized error handler that logs the error, sets status, and sends JSON response.

Node.js

app.use((err, req, res, [1]) => {
  console.error(err.[2]);
  res.status(err.status || 500).[3]({ message: err.message });
});

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

Anext

Bstack

Cjson

Dmessage

Attempts:

3 left

💡 Hint

Common Mistakes

Logging 'message' instead of 'stack'.

Using 'send' instead of 'json' for response.

Missing the 'next' parameter.

The error handler uses 'next' as the last parameter, logs the error stack, and sends a JSON response with the error message.