V8 engineers achieved a 2x performance improvement in JSON.stringify by implementing a side-effect-free fast path that bypasses expensive checks for common data objects. Key optimizations include templated string handling for different character encodings, SIMD instructions for string escaping detection, hidden class caching for object properties, replacing the Grisu3 algorithm with Dragonbox for number conversion, and using segmented buffers to eliminate costly memory reallocations. The improvements are available in V8 13.8 and benefit most typical JSON serialization use cases automatically.
Table of contents
A Side-Effect-Free Fast Path #Handling different String Representations #Optimizing String Serialization with SIMD #The Express Lane on the Fast Path #A faster double-to-string algorithm #Optimizing the underlying temporary buffer #Limitations #Conclusion #Sort: