README.md

Runtime documentation

• Performance API — WHATWG performance (hr-time, user timing, performance timeline with PerformanceObserver), per-isolate time origins for workers, the native clock hook that future requestAnimationFrame work must share, and the documented spec deviations.

• Error handling — global error/unhandledrejection events, reportError, catching native exceptions in JS (error.nativeException), forwarding JS throws to native (interop.escapeException), JS stacks on NSException, configuration flags, and crash-reporter integration.

• structuredClone — the WHATWG structuredClone(value, { transfer }) global: what clones, how graph identity and cycles are preserved, ArrayBuffer transfer, and the DataCloneError-named Error that stands in for DOMException.

• Node-API — writing a Node-API addon for this runtime: registering a module and loading it with require(), getting the napi_env from native code, the threading contract, finalizer timing, which Node-API version applies, and the divergences from Node's node_api.h.

Knowledge

Notes on work that is done, kept because the reasoning is expensive to reconstruct rather than because anything needs doing.

• V8 10.3 → 14.9 migration — the API changes and their site counts, why each non-default gn arg exists, the accessor rules that are not mechanical, and the traps that only show up at runtime.
• Resurrecting finalizers — the patch that restores WeakCallbackType::kFinalizer, removed upstream right after 10.3.22, with its invariants and test plan.