JavaScript Operations Comprehensive reference for modern JavaScript and Node.js — async patterns, module systems, runtime internals, and ES2022-2025 features. --- Async Decision Tree --- Module System Decision Tree Migration path: CJS → Dual → ESM-only --- Event Loop Quick Reference Key rules: - Microtasks always run before the next macrotask - fires before other microtasks (Promise.then) - fires in the "check" phase, after I/O callbacks - fires in "timers" phase — after I/O in same iteration --- Modern JS Cheat Sheet (ES2022–2025) | Feature | Year | Usage | |---------|------|-------| | | ES2…