Why logging matters in production in Express - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to log a message when the server starts.

Express

app.listen(3000, () => { console.log([1]); });

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

A"Server is running on port 3000"

B3000

Capp.listen

Dconsole.log

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the port number directly instead of a message.

Using app.listen inside console.log.

The console.log function prints the message to the console when the server starts.

2fill in blank

medium

Complete the code to log the HTTP method of incoming requests.

Express

app.use((req, res, next) => { console.log(req.[1]); next(); });

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

Abody

Burl

Cmethod

Dheaders

Attempts:

3 left

💡 Hint

Common Mistakes

Logging req.url instead of req.method.

Logging req.body which may be empty for GET requests.

The req.method property contains the HTTP method (GET, POST, etc.) of the request.

3fill in blank

hard

Fix the error in the logging middleware to correctly log the request URL.

Express

app.use((req, res, next) => { console.log(req.[1]); next(); });

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

Arequest_url

Bpath

CrequestUrl

Durl

Attempts:

3 left

💡 Hint

Common Mistakes

Using req.path which only gives the path without query string.

Using non-existent properties like requestUrl.

The correct property to get the full URL path is req.url. Other options are invalid and cause errors.

4fill in blank

hard

Fill both blanks to log the status code and response time after a request finishes.

Express

app.use((req, res, next) => {
  const start = Date.now();
  res.on('finish', () => {
    console.log(`Status: ${res.[1], Time: ${Date.now() - start}[2]`);
  });
  next();
});

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

AstatusCode

Bstatus

Cms

Dms()

Attempts:

3 left

💡 Hint

Common Mistakes

Using res.status which is a function, not a property.

Using ms() which is not defined.

res.statusCode gives the HTTP status code. Adding 'ms' as a string shows milliseconds for response time.

5fill in blank

hard

Fill all three blanks to create a simple logger that logs method, URL, and timestamp.

Express

app.use((req, res, next) => {
  const time = new Date().[1]();
  console.log(`[${time}] ${req.[2] ${req.[3]`);
  next();
});

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

AtoISOString

Bmethod

Curl

DgetTime

Attempts:

3 left

💡 Hint

Common Mistakes

Using getTime() which returns a number, not a string.

Mixing up method and url properties.

toISOString() gives a readable timestamp. req.method and req.url log the request details.