How do I write V8-optimized JavaScript for Node.js?
Keep types stable for hot code (V8 optimizes based on type feedback), initialize objects with all properties to avoid hidden class changes, avoid delete which deoptimizes, keep hot functions monomorphic, be careful with try/catch in hot loops, and keep arrays homogeneous.
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More FAQs in How to Write V8-Optimized JavaScript for Node.js
V8 uses hidden classes to track object shapes. Adding or deleting properties after creation changes the hidden class, which deoptimizes. Initialize objects with all their properties up front to keep the hidden class stable.
Because V8 optimizes based on type feedback. If a function consistently takes the same types, TurboFan optimizes it well. If types change often, V8 deoptimizes. Stable types enable better optimization for hot code.
Because the delete operator changes an object's hidden class, which deoptimizes the code in V8. Set properties to undefined or null instead, or restructure the object differently, to keep the hidden class stable.
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