How does Chrome's V8 engine work?

V8 Engine Working Principles

V8 is Chrome browser's JavaScript engine, developed by Google and written in C++.

Core Components

1. Parser: Parses JavaScript code into Abstract Syntax Tree (AST)
2. Interpreter: Quickly generates and executes bytecode
3. Compiler: Compiles hot code into efficient machine code
4. Garbage Collector: Automatically manages memory

Execution Flow

1. Parsing Phase: JavaScript code is parsed into AST
2. Bytecode Generation: Interpreter converts AST to bytecode
3. Execution Phase: Interpreter executes bytecode
4. Optimization Compilation: Hot code is marked, compiler compiles it into optimized machine code
5. Deoptimization: When optimization assumptions fail, code falls back to interpreted execution

Garbage Collection Mechanism

V8 uses generational garbage collection strategy:

• New Generation: Stores short-lived objects, uses Scavenge algorithm
• Old Generation: Stores long-lived objects, uses mark-sweep and mark-compact algorithms

Performance Optimization Tips

• Avoid using delete operator in hot code
• Use object literals instead of constructors
• Avoid creating new objects in loops
• Use static types for arrays and objects
• Use closures properly to avoid memory leaks