fork for Node.js child processes in Node.js - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the fork method in Node.js do?

It creates a new child process that runs a separate Node.js script. This allows running code in parallel without blocking the main program.

beginner

How do parent and child processes communicate when using fork?

They communicate via a built-in IPC channel. Parent uses child.send() and child.on('message'); child uses process.send() and process.on('message').

intermediate

What is a common use case for using fork in Node.js?

To run CPU-heavy tasks or separate workloads in parallel without blocking the main event loop, improving performance and responsiveness.

beginner

Which module do you need to import to use <code>fork</code> in Node.js?

You need to import the <code>child_process</code> module using <code>const { fork } = require('child_process');</code>.

intermediate

What happens if the child process created by fork exits unexpectedly?

The parent process can listen for the 'exit' or 'close' events on the child process object to handle cleanup or restart the child.

What does fork return in Node.js?

A A Promise

B A boolean indicating success

C A string with the child process ID

D A ChildProcess object

fork returns a ChildProcess object that represents the new child process.

Which method is used to send a message from the parent to the child process?

A child.send()

B process.send()

C child.emit()

D process.emit()

The parent uses child.send() to send messages to the child process.

How does the child process listen for messages from the parent?

A process.receive('message', callback)

B child.on('message', callback)

C process.on('message', callback)

D child.receive('message', callback)

The child listens on its own process object for 'message' events.

Which module must be imported to use fork?

A process

B child_process

C cluster

D os

fork is part of the child_process module.

What is a key benefit of using fork over exec or spawn?

A Built-in communication channel between parent and child

B Runs shell commands directly

C Consumes less memory

D Automatically restarts on failure

fork creates a Node.js child process with a communication channel, unlike exec or spawn.

Explain how to create a child process using fork and how the parent and child communicate.

Think about the steps to start and talk between processes.

Describe a scenario where using fork improves a Node.js application's performance.

Consider tasks that slow down the main program.