sdlc-decorator-patterns

NestJS decorator usage: built-in route/param/class decorators, custom decorators via createParamDecorator and SetMetadata, metadata reflection via Reflector. Apply when designing controllers, guards, interceptors, or custom decorators. Use this skill to: - Pick the right built-in decorator for routes, params, and DI. - Compose decorators (@UseGuards(A, B) @UseInterceptors(C)). - Build custom param decorators (e.g., @CurrentUser()). - Use metadata for role-based logic (Reflector + SetMetadata). - Avoid common decorator mistakes. Do NOT use this skill for: - General module/DI patterns (see nest-conventions). - GraphQL-specific decorators (see nest-advanced). - ORM entity decorators (see nest-data-layer).