Node.js Core Modules & Event Loop

Question 1

What is the event loop in Node.js?

Accepted Answer

A mechanism that handles asynchronous operations by executing callbacks when I/O operations complete

Answer

The event loop is Node.js's core mechanism for non-blocking I/O. It continuously checks for pending callbacks, timers, and I/O operations, executing them when ready without blocking the main thread.

Question 2

What is the purpose of the 'fs' module in Node.js?

Accepted Answer

To interact with the file system for reading, writing, and manipulating files

Answer

The 'fs' (file system) module provides an API for interacting with the file system, including reading files, writing files, creating directories, and managing file permissions.

Question 3

What is the difference between 'process.nextTick()' and 'setImmediate()' in Node.js?

Accepted Answer

process.nextTick() executes before any I/O events; setImmediate() executes after the current I/O poll phase

Answer

process.nextTick() fires immediately after the current operation completes, before the event loop continues. setImmediate() fires on the next iteration of the event loop, after I/O events.

Question 4

What does 'require()' do in Node.js?

Accepted Answer

Imports and caches a module, returning its exports

Answer

require() loads a module (built-in, npm package, or local file), executes it, caches the result, and returns the module's exports object for use in the current file.

Question 5

What is the Buffer class used for in Node.js?

Accepted Answer

To handle binary data directly without converting to strings

Answer

The Buffer class provides a way to handle raw binary data in Node.js, essential for working with file systems, network protocols, and streams that deal with bytes rather than strings.

Node.js Practice Test

Node.js Practice Test

Node.js Core Modules & Event Loop