IPC communication between processes in Node.js - Mini Project: Build & Apply

IPC Communication Between Processes in Node.js

📖 Scenario: You are building a simple Node.js application where a parent process sends a message to a child process, and the child process responds back. This simulates two processes communicating using IPC (Inter-Process Communication).

🎯 Goal: Create two Node.js scripts: one for the parent process and one for the child process. The parent will send a message to the child, and the child will send a reply back. You will use Node.js's child_process module and IPC channels to achieve this.

📋 What You'll Learn

Create a child process using fork from child_process module

Send a message from the parent process to the child process

Receive the message in the child process and send a reply back

Handle the reply message in the parent process

💡 Why This Matters

🌍 Real World

Many Node.js applications use child processes to run tasks in parallel or isolate work. IPC lets these processes talk to each other safely.

💼 Career

Understanding IPC in Node.js is important for backend developers working on scalable systems, microservices, or tools that require process management.

1

Create the child process script

Create a file named child.js. Inside it, write code to listen for messages from the parent process using process.on('message'). When a message is received, send back a reply message { reply: 'Hello from child' } using process.send().

Node.js

// Your code here to listen for messages and reply

Need a hint?

Use process.on('message', callback) to listen for messages and process.send() to send a reply.

2

Create the parent process script and fork the child

Create a file named parent.js. Import fork from child_process. Use fork to start the child.js script as a child process and save it in a variable called childProcess.

Node.js

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

// Your code here to fork child.js

Need a hint?

Use const childProcess = fork('./child.js') to start the child process.

3

Send a message from parent to child and listen for reply

In parent.js, send a message { greeting: 'Hello from parent' } to childProcess using childProcess.send(). Then listen for messages from the child using childProcess.on('message') and save the reply in a variable called childReply.

Node.js

childProcess.send({ greeting: 'Hello from parent' });

// Your code here to listen for reply and save it in childReply

Need a hint?

Use childProcess.send() to send and childProcess.on('message', callback) to receive messages.

4

Complete the IPC communication setup

Add code in parent.js to log the childReply variable inside the childProcess.on('message') callback to confirm the reply was received.

Node.js

childProcess.on('message', (msg) => {
    childReply = msg.reply;
    // Your code here to log childReply
});

Need a hint?

Use console.log() inside the message listener to show the reply.