Why child processes are needed in Node.js - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a child process using Node.js.

Node.js

const { spawn } = require('[1]');
const child = spawn('ls', ['-lh', '/usr']);

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

Apath

Bfs

Chttp

Dchild_process

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'fs' or 'http' instead of 'child_process' to spawn processes.

Node.js uses the child_process module to create child processes.

2fill in blank

medium

Complete the code to listen for data from the child process's stdout.

Node.js

child.stdout.on('[1]', (data) => {
  console.log(`Output: ${data}`);
});

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Adata

Bclose

Cexit

Derror

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'exit' or 'close' event instead of 'data' to get output.

The data event is emitted when the child process sends output.

3fill in blank

hard

Fix the error in the code to correctly handle child process exit.

Node.js

child.on('[1]', (code) => {
  console.log(`Child exited with code ${code}`);
});

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Aclose

Bexit

Cdata

Derror

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'close' event instead of 'exit' to detect process end.

The exit event is emitted when the child process ends.

4fill in blank

hard

Fill both blanks to create a child process that runs a script and handle errors.

Node.js

const child = require('child_process').[1]('node', ['script.js']);
child.on('[2]', (err) => {
  if (err) console.error('Error:', err);
});

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Aspawn

Bexit

Cerror

Dfork

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'exit' event to catch errors instead of 'error'.

Using 'fork' when 'spawn' is intended.

spawn starts a new process, and error event handles errors.

5fill in blank

hard

Fill all three blanks to create a child process, listen for output, and handle exit.

Node.js

const { [1] } = require('child_process');
const child = [2]('ls', ['-la']);
child.on('[3]', (code) => {
  console.log(`Process ended with code ${code}`);
});

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

Aspawn

Bchild_process

Cexit

Dfork

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up 'fork' and 'spawn'.

Listening for 'close' instead of 'exit' event.

Destructure spawn from the child_process module, use spawn to create the process, and listen for exit event.