How can you help V8 optimize your JavaScript code?
Initialize all properties in the constructor (same order), do not add or delete properties after construction, keep functions monomorphic (same argument types), avoid eval/with/delete, and use arrays for contiguous numeric data.
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More FAQs in How V8 Optimizes JavaScript Code
V8 uses hidden classes (stable object shapes), inline caching (cached property locations), and TurboFan (optimized machine code for hot functions). It collects feedback and deoptimizes when assumptions break.
Internal labels assigned to objects based on their shape (property names and order). Objects with the same hidden class share optimized code. Different shapes create new hidden classes, causing deoptimization and slower code.
V8 caches the memory location of a property accessed in a hot function. Next time, it directly reads from the cached location (fast). If the hidden class changes, the cache is invalidated and the function deoptimizes.
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