NodeJS

Builds, debugs, and hardens Node.js servers, CLIs, and npm packages: async, modules, streams, memory, and process lifecycle. Use when writing or reviewing code that runs on Node, when a process hangs or refuses to exit, leaks memory, gets OOM-killed, pins one CPU core at 100%, or dies on an unhandled rejection; when the error reads EADDRINUSE, EMFILE, ECONNRESET, ERR_MODULE_NOT_FOUND, ERR_REQUIRE_ESM, or "__dirname is not defined"; when import and require interop breaks, streams buffer everything in RAM, a server returns intermittent 502s behind a load balancer, or SIGTERM drops in-flight requests; when npm install, lockfiles, peer dependencies, workspaces, native module builds, or publishing misbehave; when a suite passes locally and fails in CI; or when containerizing, profiling, and shutting down a service cleanly. Not for browser-only JavaScript, TypeScript type-system design, or the Bun and Deno runtimes.