CPU profiling basics in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start CPU profiling using Node.js built-in profiler.

Node.js

const profiler = require('inspector');
profiler.[1]();

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

AbeginProfiling

BstartProfiling

CinitProfiling

DlaunchProfiling

Attempts:

3 left

💡 Hint

Common Mistakes

Using a method name that does not exist like 'beginProfiling'.

Trying to call 'launchProfiling' which is not part of the inspector API.

The startProfiling method starts the CPU profiler session in Node.js.

2fill in blank

medium

Complete the code to stop CPU profiling and save the profile data.

Node.js

const inspector = require('inspector');
const session = new inspector.Session();
session.connect();
session.post('Profiler.[1]', () => {
  session.disconnect();
});

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

Astop

Bpause

Cend

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'pause' which only temporarily halts profiling.

Using 'end' which is not a valid command in this context.

The stop command stops the CPU profiler and returns the profile data.

3fill in blank

hard

Fix the error in the code to correctly enable CPU profiling in Node.js.

Node.js

const inspector = require('inspector');
const session = new inspector.Session();
session.connect();
session.post('Profiler.[1]');

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

AstartProfiling

Bbegin

Cactivate

Denable

Attempts:

3 left

💡 Hint

Common Mistakes

Calling 'startProfiling' without enabling the profiler first.

Using non-existent commands like 'begin' or 'activate'.

The enable command must be called before starting profiling to activate the profiler.

4fill in blank

hard

Fill both blanks to create a CPU profile and save it to a file named 'profile.cpuprofile'.

Node.js

const fs = require('fs');
const inspector = require('inspector');
const session = new inspector.Session();
session.connect();
session.post('Profiler.enable');
session.post('Profiler.start', () => {
  setTimeout(() => {
    session.post('Profiler.[1]', (err, [2]) => {
      if (!err) {
        fs.writeFileSync('profile.cpuprofile', JSON.stringify([2]));
      }
      session.disconnect();
    });
  }, 1000);
});

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

Astop

Bprofile

Cdata

Dresult

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong command names like 'end' instead of 'stop'.

Using incorrect variable names for the profile data.

The stop command stops profiling and returns the profile data object.

5fill in blank

hard

Fill all three blanks to start profiling, enable the profiler, and then stop profiling correctly.

Node.js

const inspector = require('inspector');
const session = new inspector.Session();
session.connect();
session.post('Profiler.[1]');
session.post('Profiler.[2]', () => {
  setTimeout(() => {
    session.post('Profiler.[3]', (err, profile) => {
      if (!err) {
        console.log('Profile collected');
      }
      session.disconnect();
    });
  }, 500);
});

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

Aenable

Bstart

Cstop

Dpause

Attempts:

3 left

💡 Hint

Common Mistakes

Skipping the enable step.

Using 'pause' instead of 'stop' to end profiling.

You must first enable the profiler, then start it, and finally stop it to collect the profile.