• Coding
• Tutorials
• AUTHOR: codevision AI engine
• DZone JavaScript

This article explores how JavaScript engines optimize code at runtime, focusing on JIT compilation, object shapes, and best practices for writing efficient code. It explains the three main stages of JavaScript execution: AST generation, bytecode compilation, and JIT optimization. The author, Akim Mamedov, provides insights into how developers can structure their code to enable the engine to optimize effectively. Understanding these processes is essential for writing performant JavaScript. The article is worth reading because it offers practical strategies to improve code efficiency. Readers will learn how to write JavaScript that leverages engine optimizations for better performance.

Key facts

• JavaScript engines optimize code during runtime using strategies like JIT compilation.
• The execution of JavaScript code involves three main stages: AST generation, bytecode compilation, and JIT optimization.
• Maintaining consistent object shapes and type stability helps the engine optimize code more effectively.
• JIT compilers gather runtime data to create efficient machine code for frequently executed code paths.
• Deoptimization occurs when the engine’s assumptions about data types or structures change, leading to performance drops.