Get V8 optimization status

get-v8-optimization-status.js

// https://github.com/v8/v8/blob/master/test/mjsunit/mjsunit.js#L162-L178
const statuses = {
  IsFunction: 1 << 0,
  NeverOptimize: 1 << 1,
  AlwaysOptimize: 1 << 2,
  MaybeDeopted: 1 << 3,
  Optimized: 1 << 4,
  TurboFanned: 1 << 5,
  Interpreted: 1 << 6,
  MarkedForOptimization: 1 << 7,
  MarkedForConcurrentOptimization: 1 << 8,
  OptimizingConcurrently: 1 << 9,
  IsExecuting: 1 << 10,
  TopmostFrameIsTurboFanned: 1 << 11,
  LiteMode: 1 << 12,
  MarkedForDeoptimization: 1 << 13,
}

const getStatus = (fn) => {
  const status = %GetOptimizationStatus(fn)

  return Object.entries(statuses).filter(([, value]) => status & value).map(([key]) => key)
}

const printStatus = (fn) => console.log(fn.name + ':', getStatus(fn).join(', '))