nodejs-best-practices

Fastify suits simple to medium REST APIs with built-in validation and better performance than Express. NestJS fits complex enterprise apps needing dependency injection and modules. Hono works for minimal edge-compatible microservices.

Use Promise.all for independent operations that must all succeed, and Promise.allSettled when partial failure is acceptable. Avoid awaiting inside loops, which forces unnecessary sequential execution.

Enable strict: true, noUncheckedIndexedAccess, and exactOptionalPropertyTypes. These catch undefined array access and distinguish optional properties from explicit undefined values at compile time.

Validate process.env at startup with a Zod schema defining types, defaults, and constraints for each variable. If validation fails, the process exits immediately with a clear message about what is missing.

console.log produces unstructured output that cannot be filtered or queried by log aggregation systems. Use pino for structured JSON logging with contextual fields like userId and action on every entry.

Use a Result discriminated union for expected errors like validation failures, making error paths explicit in function signatures. Reserve try/catch for truly exceptional cases and unexpected failures.