Heap snapshot for memory leaks in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the module used to take heap snapshots in Node.js.

Node.js

const heapdump = require('[1]');

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

Aheapdump

Bhttp

Cfs

Dexpress

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'fs' or 'http' instead of 'heapdump'.

Forgetting to install the 'heapdump' module before requiring it.

The heapdump module is used to take heap snapshots in Node.js for memory leak analysis.

2fill in blank

medium

Complete the code to trigger a heap snapshot save with a filename.

Node.js

heapdump.writeSnapshot('[1]', (err, filename) => {
  if (err) console.error(err);
  else console.log('Snapshot saved to', filename);
});

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

Aleak.heapsnapshot

Bsnapshot.heapsnapshot

Cmemory.heapsnapshot

Dheap.heapsnapshot

Attempts:

3 left

💡 Hint

Common Mistakes

Using filenames without the '.heapsnapshot' extension.

Using unrelated names like 'leak.heapsnapshot' without context.

The filename for the heap snapshot is usually given with a .heapsnapshot extension, such as 'memory.heapsnapshot'.

3fill in blank

hard

Fix the error in the code to correctly listen for a signal to trigger a heap snapshot.

Node.js

process.on('[1]', () => {
  heapdump.writeSnapshot();
});

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

ASIGTERM

BSIGUSR2

CSIGKILL

DSIGINT

Attempts:

3 left

💡 Hint

Common Mistakes

Using SIGINT or SIGTERM which terminate the process.

Using SIGKILL which cannot be caught.

SIGUSR2 is commonly used to trigger heap snapshots in Node.js without stopping the process.

4fill in blank

hard

Fill both blanks to create a heap snapshot filename with a timestamp.

Node.js

const filename = `heap-[1]-[2].heapsnapshot`;

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

ADate.now()

Bnew Date()

Cprocess.pid

DMath.random()

Attempts:

3 left

💡 Hint

Common Mistakes

Using new Date() directly in filename without formatting.

Using Math.random() which is not descriptive.

Using Date.now() gives a timestamp, and process.pid adds the process ID to the filename for uniqueness.

5fill in blank

hard

Fill all three blanks to write a heap snapshot and log the filename with error handling.

Node.js

heapdump.writeSnapshot([1], ([2], [3]) => {
  if ([2]) console.error([2]);
  else console.log('Snapshot saved:', [3]);
});

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

A'snapshot.heapsnapshot'

Berr

Cfilename

D'memory.heapsnapshot'

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up error and filename parameters in the callback.

Using incorrect filename strings.

The first blank is the filename string, the second is the error parameter, and the third is the filename parameter in the callback.