Node.jsprocess là global object không cần require. process.env: chứa environment variables — KHÔNG bao giờ log toàn bộ process.env vì chứa secrets; validate với zod/envalid ngay startup để fail fast nếu thiếu. process.argv: array [nodePath, scriptPath, ...userArgs] — dùng yargs hoặc commander để parse thay vì thủ công.
Signal handling: process.on('SIGTERM', gracefulShutdown) — xử lý khi container/PM2 dừng process (close DB connections, finish in-flight requests); SIGINT = Ctrl+C. process.memoryUsage() trả về { rss, heapTotal, heapUsed, external } — monitor memory leaks bằng cách log định kỳ. process.hrtime.bigint() cho high-resolution timestamps (nanoseconds) để benchmark code. process.exit(1) exit với error code — quan trọng cho CI pipelines biết lệnh fail. process.on('uncaughtException') và process.on('unhandledRejection') — log error rồi process.exit(1), không recover vì process state có thể corrupt.
process is a global object requiring no require. process.env: contains environment variables — NEVER log the entire process.env as it contains secrets; validate with zod/envalid at startup to fail fast if anything is missing. process.argv: array [nodePath, scriptPath, ...userArgs] — use yargs or commander to parse instead of doing it manually.
Signal handling: process.on('SIGTERM', gracefulShutdown) — handles when a container/PM2 stops the process (close DB connections, finish in-flight requests); SIGINT = Ctrl+C. process.memoryUsage() returns { rss, heapTotal, heapUsed, external } — monitor memory leaks by logging periodically. process.hrtime.bigint() for high-resolution timestamps (nanoseconds) to benchmark code. process.exit(1) exits with an error code — important for CI pipelines to detect failures. process.on('uncaughtException') and process.on('unhandledRejection') — log the error then process.exit(1), don't try to recover as process state may be corrupted.