AgentSkillsCN

architecture-ddd

领域驱动设计模式、分层边界（表现层 → 应用层 → 领域层 ← 基础设施层）、战术模式（实体、值对象、聚合、仓库），以及事件驱动流程指导。当您设计新功能、跨层重构，或强化 DDD 架构边界时，可使用此技能。

SKILL.md
--- frontmatter
name: architecture-ddd
description: Domain-Driven Design patterns, layer boundaries (Presentation → Application → Domain ← Infrastructure), tactical patterns (entities, value objects, aggregates, repositories), and event-driven flow guidance. Use when designing new features, refactoring across layers, or enforcing DDD architectural boundaries.

SKILL: Architecture & DDD Master Guide

This document defines the Domain-Driven Design (DDD) architecture and strict layer boundaries for the project.

🏛️ 1. Layered Architecture (The Law)

Dependencies must flow inward: Presentation → Application → Domain ← Infrastructure.

🔴 Domain Layer (src/app/domain/)

  • •Purity: Zero framework dependencies (No Angular, No Firebase, No RxJS).
  • •Entities: Minimal, intention-free models.
  • •Value Objects: Immutable, validated at creation.
  • •Repositories: Interfaces ONLY (ports).
  • •Aggregates: Transactional boundaries.
  • •Domain Events: Immutable "facts" that have occurred.

🟡 Application Layer (src/app/application/)

  • •Orchestration: Implements Use Cases (Handlers).
  • •State: NgRx Signals (Store) is the source of truth.
  • •Mappers: Domain ↔ DTO / ViewModel conversion.
  • •Ports: Defines repository and service interfaces.

🔵 Infrastructure Layer (src/app/infrastructure/)

  • •Adapters: Implements interfaces defined in the application/domain layers.
  • •Technical: Firebase, HTTP, persistence, logging, external SDKs.
  • •DTOs: Confined to this layer; never leaked to Presentation or Domain.

🟢 Presentation Layer (src/app/presentation/)

  • •UI Only: No business logic.
  • •Signals: Consumes signals from stores.
  • •Standalone: All components are standalone + zone-less.

🧩 2. Tactical DDD Patterns

Repository Pattern

  • •Interface defined in Domain or Application.
  • •Implementation hidden in Infrastructure.
  • •Injection via InjectionToken to ensure loose coupling.

Domain Service

  • •Used when logic involves multiple entities or doesn't naturally fit into one.
  • •Must remain pure (no I/O).

Event-Driven Flow

  1. •Append: Persist a command outcome to the store/database.
  2. •Publish: Emit event via the EventBus.
  3. •React: Other stores or capabilities listen and react.

📦 3. Project Structure & Naming

LayerTypePattern
DomainEntity{name}.entity.ts
ApplicationStore{name}.store.ts
InfrastructureRepository{name}-firestore.repository.ts
PresentationComponent{name}.component.ts
  • •Alias Imports: Use @domain/*, @application/*, @infrastructure/*.
  • •No Relative Imports: Never import across layers using ../../.

🪒 4. Occam's Razor

  • •Minimalism: Do not add layers or abstractions without necessity.
  • •Cohesion: Keep related logic close.
  • •Decoupling: Minimize dependencies between modules.

Adjudication: TypeScript errors (TS2339, TS2345) regarding cross-layer imports or invalid field access in the Domain are architectural violations—fix the design, do not suppress the error.