Why process management matters in Node.js - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a child process that runs a Node.js script.

Node.js

const { spawn } = require('child_process');
const child = spawn('node', ['[1]']);

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

Aserver.json

Bindex.html

Cstyle.css

Dapp.js

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-JavaScript file like HTML or CSS as the script to run.

The spawn function starts a new process running the specified script. Here, app.js is the Node.js script to run.

2fill in blank

medium

Complete the code to listen for the 'exit' event of the child process.

Node.js

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

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

Astart

Berror

Cexit

Dclose

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'start' or 'close' instead of 'exit' event.

The 'exit' event fires when the child process finishes. Listening to it helps know when the process ends.

3fill in blank

hard

Fix the error in the code to correctly kill the child process.

Node.js

child.[1]('SIGTERM');

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

Astop

Bkill

Cterminate

Dend

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent methods like 'stop' or 'terminate'.

The kill method sends a signal to terminate the child process. Other options are not valid methods.

4fill in blank

hard

Fill both blanks to spawn a child process with arguments and handle errors.

Node.js

const child = spawn('node', ['[1]']);
child.on('[2]', (err) => {
  console.error('Failed to start child process:', err);
});

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

Ascript.js

Berror

Cexit

Dapp.js

Attempts:

3 left

💡 Hint

Common Mistakes

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

The first blank is the script to run. The second blank is the 'error' event to catch startup failures.

5fill in blank

hard

Fill all three blanks to spawn a child process, listen for exit, and send a kill signal.

Node.js

const child = spawn('[1]', ['[2]']);
child.on('[3]', (code) => {
  console.log(`Process exited with code ${code}`);
  child.kill('SIGINT');
});

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

Anode

Bserver.js

Cexit

Derror

Attempts:

3 left

💡 Hint

Common Mistakes

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

The first blank is the command 'node'. The second is the script 'server.js'. The third is the 'exit' event to detect process end.