Worker thread vs child process in Node.js - Hands-On Comparison

Worker Thread vs Child Process in Node.js

📖 Scenario: You are building a Node.js application that needs to perform heavy calculations without blocking the main program. You want to learn how to use worker_threads and child_process modules to run tasks in parallel.

🎯 Goal: Create a simple Node.js app that uses a worker thread and a child process to run the same calculation separately. You will see how to set up both and send messages between the main program and these parallel workers.

📋 What You'll Learn

Create a worker thread using the worker_threads module

Create a child process using the child_process module

Send a number from the main thread to both the worker thread and child process

Receive the squared result back from both and log it

Use exact variable and function names as instructed

💡 Why This Matters

🌍 Real World

Node.js apps often need to run heavy tasks without freezing the main program. Worker threads and child processes help by running code in parallel.

💼 Career

Understanding these parallel processing methods is important for backend developers to build efficient, responsive Node.js applications.

1

Set up the main data and imports

Create a variable called number and set it to 7. Import Worker from worker_threads and fork from child_process.

Node.js

const { Worker } = require('worker_threads');
const { fork } = require('child_process');

const number = 7;
// Your code here

Need a hint?

Use const number = 7; and import Worker and fork exactly as shown.

2

Create a worker thread to calculate square

Create a new Worker instance called worker that runs a file named 'worker.js'. This worker will receive the number and calculate its square.

Node.js

const { Worker } = require('worker_threads');
const { fork } = require('child_process');

const number = 7;

const worker = new Worker('./worker.js');
// Your code here

Need a hint?

Use new Worker('./worker.js') to create the worker thread.

3

Create a child process to calculate square

Create a child process called child using fork to run a file named 'child.js'. This child process will also receive the number and calculate its square.

Node.js

const { Worker } = require('worker_threads');
const { fork } = require('child_process');

const number = 7;

const worker = new Worker('./worker.js');

const child = fork('./child.js');
// Your code here

Need a hint?

Use fork('./child.js') to create the child process.

4

Send number and receive results from worker and child

Send the number to both worker and child. Listen for messages from both using worker.on('message', ...) and child.on('message', ...). Log the results with console.log using the exact text: "Worker result: " and "Child result: " followed by the squared number.

Node.js

const { Worker } = require('worker_threads');
const { fork } = require('child_process');

const number = 7;

const worker = new Worker('./worker.js');

const child = fork('./child.js');

worker.postMessage(number);
worker.on('message', (result) => {
  // Your code here
});

child.send(number);
child.on('message', (result) => {
  // Your code here
});

Need a hint?

Use postMessage and send to send data. Use on('message') to receive and console.log to print results.