fork for Node.js child processes in Node.js - Mini Project: Build & Apply

Using fork for Node.js Child Processes

📖 Scenario: You are building a Node.js application that needs to perform a heavy calculation without blocking the main program. To do this, you will create a child process using fork to run the calculation separately.

🎯 Goal: Build a Node.js script that uses fork from the child_process module to run a child process. The child process will send a message back to the parent process when it finishes a task.

📋 What You'll Learn

Create a main script that uses fork to start a child process

Create a child script that sends a message back to the parent process

Set up a message listener in the parent to receive messages from the child

Log the message received from the child process in the parent

💡 Why This Matters

🌍 Real World

Using child processes helps keep Node.js applications responsive by offloading heavy or blocking tasks to separate processes.

💼 Career

Understanding how to use fork and child processes is important for backend developers working with Node.js to build scalable and efficient applications.

1

Create the child process script

Create a file named child.js with a single line that sends the message 'Task complete' to the parent process using process.send().

Node.js

// Your code here to send 'Task complete' message to parent

Need a hint?

Use process.send('Task complete') to send a message from the child process to the parent.

2

Import fork in the main script

In a new file named parent.js, import the fork function from the child_process module using const { fork } = require('child_process');.

Node.js

const { fork } = require('child_process');
// Your code here

Need a hint?

Use const { fork } = require('child_process'); to import fork.

3

Fork the child process and listen for messages

In parent.js, use fork to start child.js and assign it to a variable named child. Then add a listener on child for the message event that receives a parameter msg.

Node.js

const { fork } = require('child_process');
// Fork child.js and listen for messages

Need a hint?

Use fork('./child.js') to start the child process and child.on('message', (msg) => { ... }) to listen for messages.

4

Log the message received from the child process

Inside the message event listener in parent.js, add a line to log the received msg to the console using console.log(msg);.

Node.js

const { fork } = require('child_process');
const child = fork('./child.js');
child.on('message', (msg) => {
  // Log the message here
});

Need a hint?

Use console.log(msg); to print the message from the child process.