agent_skills_nodejs_nestjs

Defines the rule base every skill in this pack obeys: file layout, frontmatter, vocabulary, OOP/typing/decoupling axioms, and anti-patterns. Load FIRST before authoring or applying any other skill in this pack.

Designs NestJS feature modules with clean dependency boundaries, provider scopes, and dynamic modules. Use when adding a new feature module, splitting a monolithic AppModule, or fixing tangled imports between modules.

Builds thin NestJS controllers that parse input, invoke a single use case, and map the Result to ApiResponse<T>. Use when adding HTTP endpoints, refactoring fat controllers, or applying API versioning.

Prepares a NestJS service for production: graceful shutdown, health/readiness, structured logs, config, Dockerfile, CI gates, and rollout safety. Use when promoting a service to staging/production or auditing readiness.

Designs NestJS application services as use-case classes that orchestrate domain logic and ports without leaking the framework. Use when creating new use cases, refactoring services that mix HTTP/DB/domain, or moving from anemic services to OOP.

Maps internal AppError hierarchy to HTTP responses through a single global exception filter and a Result-to-HttpException helper. Use when adding new error types, fixing inconsistent error responses, or removing scattered try/catch in controllers.

Implements the Repository pattern with TypeORM in NestJS so domain entities stay framework-free, ORM models live in infrastructure, and transactions are explicit. Use when adding persistence, refactoring leaky ORM usage, or handling transactions across aggregates.

Tests NestJS applications at unit, integration, and e2e levels using Test.createTestingModule and Supertest with hand-rolled fakes. Use when writing tests for use cases, controllers, or full HTTP flows.

Applies pipes, guards, and interceptors for cross-cutting concerns in NestJS — validation, auth, transformation, logging, caching. Use when implementing auth, response shaping, observability, or any concern that should not live in controllers.

Validates NestJS request payloads with class-validator and class-transformer using a global ValidationPipe. Use when adding/refactoring DTOs, hardening boundary input, or removing manual validation from controllers.

Applies GoF and DDD design patterns in TypeScript: Factory, Repository, Strategy, Adapter, Decorator, Facade, Observer, Command, Specification. Use when picking the right structure for a feature or refactoring duplicated logic.

Decouples modules using ports, adapters, and a DI container (tsyringe / inversify / NestJS). Use when wiring services, removing direct imports of concrete classes, or breaking circular dependencies.

Designs classes and class hierarchies in TypeScript using SOLID, encapsulation, and immutability. Use when creating new domain entities, application services, or refactoring procedural code into OOP.

Defines a typed error hierarchy, distinguishes expected business failures from unexpected programmer errors, and forbids swallowing errors. Use when creating new error types, mapping errors to HTTP, or reviewing try/catch usage.

Adds structured JSON logging, correlation/trace IDs, metrics, and health endpoints. Use when wiring observability for a new service, debugging cross-service requests, or removing console.log.

Loads and validates configuration once at boot through a typed schema (Zod / class-validator), preventing scattered process.env access and runtime surprises. Use when adding env vars, debugging config-related crashes, or onboarding a new environment.

Sets the baseline tooling and tsconfig for any Node.js TypeScript project: strict compiler flags, ESLint, Prettier, package layout, npm scripts. Use when bootstrapping a new project or auditing an existing one for foundational quality.

Hardens Node.js HTTP services: input validation, secure headers, authentication/authorization basics, secret handling, and dependency hygiene. Use when shipping to production or reviewing a service for security gaps.

Separates code into domain, application, and infrastructure layers so business rules stay framework-free and testable. Use when designing a new feature, splitting a god service, or moving rules out of controllers.

Specifies folder structure, module boundaries, barrels, and path aliases for a Node.js TypeScript project. Use when starting a new repo, adding a new feature module, or refactoring tangled imports.

Writes unit, integration, and contract tests for TypeScript services using Vitest/Jest with hand-rolled fakes. Use when adding tests, refactoring untestable code, or designing the test strategy for a feature.

Defines generic types for cross-boundary data: ApiResponse<T>, Paginated<T>, Result<T,E>, Repository<T,ID>. Use when designing HTTP responses, use-case return types, or persistence ports.