What problem does it solve? Building Node.js backends often leads to tangled code where business logic is coupled to frameworks, databases, and HTTP libraries, making the system hard to test and change. This Skill enforces Hexagonal Architecture (Ports and Adapters) so your core domain stays pure, dependencies point inward, and adapters can be swapped without touching business logic. ## Core Features & Use Cases - Strict Layer Boundaries: Defines a project structure separating core domain, application use cases, inbound/outbound adapters, and a DI composition root, with rules banning framework imports in the core. - Ports via TypeScript Interfaces: Establishes inbound and outbound port contracts (e.g., UserRepository, Clock) with constructor injection, so dependencies fail at composition time rather than in production. - Testing & Governance Guidance: Prescribes vitest unit tests with in-memory port fakes, testcontainers integration tests, UTC datetime governance, and a currency baseline (Node 22, pnpm, zod, prisma). - Use Case: When scaffolding a new TypeScript API, apply this Skill to generate a layered codebase where swapping Postgres for another database only requires writing a new outbound adapter. ## Quick Start Ask the AI to scaffold a new TypeScript Node.js backend using hexagonal architecture with ports, adapters, and a DI container following this skill's structure.
