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@polesdesfetes (Private)

Staff engineer at Data Dog.

V8 Engine

• Takes JS as input and executes it
• Createed by Google, open source, C++
  • https://chromium.googlesource.com/v8/v8.git
• good resource
• document is not defined in V8
• Doesn't just interpret JS
  • Parse to AST
  • Ignition: bytecode generation
  • Sparkplug: fast codegen
  • Turbofan: optimized codegen
  • reminder you can define numbers as 1_000_000 in js
    • underscore in numbers
  • objects have a Map, a hidden class.
  • what is % in fromnt of functions? It's "Native syntaxes". console.log(%MaxSmi())
  • You can set V8 flages with node using require('v8').setFlags (?) ('--flag')
  • Native syntax: undocumented V8 APIs.
  • Benchmark JS for testing optimizations... optimizations DO matter, up to 2x faster for a simple add function.
  • V8OptimizationStoatus() to get the status of optimization
  • How do debuggers work?
    • Chrome Debug Protocol
      • Has a Heap profiler and CPU profiler
        • CPU profiling is done with polling, similar to the top program (?)
  • See the Torque language which compiles directly into v8 bytecode. torque