mir-backend-node

Make It Right (Node.js runtime tier). V8/Node 20+ LTS runtime reliability footguns that are shared across EVERY Node backend framework (Express, Fastify, NestJS, Hapi, Koa) — distinct from the generic backend gates and from any one framework's mechanics. Covers: the single-threaded event loop and what blocks it (sync I/O, huge JSON, synchronous crypto/zlib, long CPU loops, pathological regex), the absence of CPU parallelism on one process and how to get it (worker_threads / cluster), unhandled promise rejection crashes, serializing awaits in a loop vs. bounded Promise.all concurrency, stream backpressure, AbortController timeouts on every outbound call, uncaughtException semantics, heap limits under container memory, and async-context loss across callbacks and timers. TRIGGER when the backend runtime is Node.js / V8 — sits between mir-backend (generic gates) and the framework module (e.g. mir-backend-node-express). SKIP for Python/JVM/Go/Rust/.NET/Ruby/PHP/BEAM runtimes (each has its own mir-backend-<runtime> tier), and for framework-library mechanics (those live in the framework module).