Node.js Fundamentals: Comprehensive Review of Core Concepts

Explore the fundamentals of Node.js, including its use of the V8 JavaScript engine, event-driven architecture, and asynchronous programming. Understand how Node.js enables efficient server-side applications and network tools.

Node.js is an open-source, cross-platform JavaScript runtime built on Chrome's V8 JavaScript engine, allowing execution of JavaScript code outside of a web browser for server-side applications and network tools.

Core Concepts

1. JavaScript Engine

Node.js uses the V8 JavaScript engine, the same engine that powers Google Chrome, enabling efficient execution of JavaScript code.

2. Event-Driven Architecture

Node.js operates in a non-blocking, single-threaded manner. It handles multiple concurrent requests through an event-driven architecture, avoiding the need for multiple threads.

3. Asynchronous Programming

Asynchronous programming is crucial in Node.js due to its event-driven nature. It handles I/O operations asynchronously, allowing the event loop to process other tasks while waiting for I/O operations to complete.

4. Modules

Node.js applications are modular, with code organized into modules. Modules encapsulate functionality and are imported using the require() function.

5. Global Scope

In Node.js, global variables are not automatically created. Use module.exports or exports to export variables from a module.

Primitive Data Types

Node.js inherits primitive data types from JavaScript, including:

• String
• Number
• Boolean
• Undefined
• Null
• Symbol (introduced in ES6)

Additionally, Node.js includes the Buffer class for handling binary data.

Built-in Objects and Modules

Node.js provides several built-in objects and modules:

• process object: Provides information about the current Node.js process.
• console object: Used for logging messages.
• http module: Enables creation of HTTP servers and clients.
• fs module: Provides functions for file system interactions.

Key Differences from Browser JavaScript

• Global Scope: Global variable handling differs; Node.js uses the global object.
• No DOM: Node.js does not include a Document Object Model (DOM).
• Modules: Node.js uses a more robust module system compared to browser's <script> tags.

Loose Typing

JavaScript in Node.js supports loose typing, similar to browser JavaScript. Use the var keyword to declare variables of any type.

Object Literal

Object literal syntax is the same as in browser JavaScript.

var obj = {
    authorName: 'Ryan Dahl',
    language: 'Node.js'
}

Functions

Functions in Node.js are first-class citizens, similar to browser JavaScript. They can have attributes and properties and can be treated like classes.

function Display(x) {
    console.log(x);
}

Display(100);

Buffer

Node.js includes the Buffer class for handling binary data, which is not available in browser JavaScript. It is used for operations like reading files or receiving network packets.

process Object

The process object provides information about the current Node.js process. For example:

> process.execPath
'C:\\Program Files\\nodejs\\node.exe'
> process.pid
1652
> process.cwd()
'C:\\'

Defaults to Local

In Node.js, variables are local by default. Unlike browser JavaScript, where undeclared variables become global, Node.js requires explicit exports for global scope access.

exports.log = {
    console: function(msg) {
        console.log(msg);
    },
    file: function(msg) {
        // log to file here
    }
}

Learning Resources

• Official Node.js Documentation
• Node.js School
• JavaScript.info

Understanding these core concepts will provide a strong foundation for building server-side applications and exploring the Node.js ecosystem.