ts-backend-engineer

Structure a production-grade TypeScript backend using layered architecture with Controller, Service, and Repository boundaries. Enforce strict typing, discriminated unions, and explicit dependency injection while avoiding the any type to ensure correctness and scalable API design.

Handle errors in Node.js or Bun backend APIs by applying disciplined error handling patterns across service layers and repositories. Use strong typing and discriminated unions for safe async workflows to ensure robust stability and predictable API responses.

Yes, these TypeScript backend patterns work across Node.js, Bun, and Deno runtimes. They support REST, tRPC, and GraphQL endpoints, applying strict typing and explicit dependency injection constraints universally across popular frameworks.

Implement caching and input validation in a typed service layer by applying performance and stability patterns. Use strong typing for input shaping and safe async workflows, ensuring data validation occurs before hitting the repository layer.

Use discriminated unions for TypeScript API design to establish rigorous type-safety and guarantee correctness across server-side code. They enable disciplined error handling and predictable state management without relying on the any type.

Avoid explicit dependency injection only when bypassing strict architectural boundaries for rapid prototyping. For production-grade server-side code, explicit dependency injection is required to maintain testability and clear module separation across services and repositories.