Advanced Node.js

Chapter 1: Node.js Architecture Deep Dive

1.1 V8 Engine

Node.js is built on Chrome's V8 JavaScript engine, which compiles JavaScript to native machine code. Understanding V8 helps optimize Node.js applications.

V8 Components:

• Parser: Converts JavaScript source to Abstract Syntax Tree (AST)
• Ignition: Interpreter that generates bytecode
• TurboFan: Optimizing compiler that generates machine code
• Orinoco: Garbage collector for memory management

// V8 optimization tips
// 1. Use consistent object shapes
function createUser(name, age) {
    return { name, age }; // Same shape every time
}

// 2. Avoid hidden classes
// Bad: Different property order
function badUser(name, age) {
    if (name) this.name = name;
    if (age) this.age = age; // Different hidden class
}

// Good: Consistent property order
function goodUser(name, age) {
    this.name = name;
    this.age = age; // Same hidden class
}

1.2 LibUV

LibUV is a multi-platform C library that provides asynchronous I/O operations. It's the foundation of Node.js's event loop.

LibUV Features:

• Event loop implementation
• Thread pool for blocking operations
• File system operations
• Network I/O (TCP, UDP)
• DNS resolution
• Child processes

// LibUV thread pool
// Default size: 4 threads
// Can be increased: UV_THREADPOOL_SIZE=8 node app.js

// Operations using thread pool:
// - fs.* (except fs.FSWatcher)
// - crypto.* (some functions)
// - dns.lookup()
// - zlib.* (except zlib streams)

1.3 Node.js Architecture Layers

// Node.js Architecture:
// ┌─────────────────┐
// │   JavaScript    │  Your application code
// ├─────────────────┤
// │  Node.js Core   │  Built-in modules (fs, http, etc.)
// ├─────────────────┤
// │   V8 Engine     │  JavaScript execution
// ├─────────────────┤
// │     LibUV       │  Event loop & async I/O
// └─────────────────┘

1.4 Process and Thread Model

Node.js runs in a single process with a single main thread. The event loop runs on the main thread, while blocking operations are handled by LibUV's thread pool.

// Single-threaded event loop
console.log('Start');
setTimeout(() => console.log('Timeout'), 0);
Promise.resolve().then(() => console.log('Promise'));
console.log('End');

// Output:
// Start
// End
// Promise
// Timeout