architecture（架构）

Architecture Decision Framework

"Requirements drive architecture. Trade-offs inform decisions. ADRs capture rationale."

Selective Reading Rule

Read ONLY files relevant to the request! Check the content map, find what you need.

Core Principle

"Simplicity is the ultimate sophistication."

• Start simple
• Add complexity ONLY when proven necessary
• You can always add patterns later
• Removing complexity is MUCH harder than adding it

Code Style Rules

General Principles

• Early return pattern: Always use early returns over nested conditions for better readability
• Avoid code duplication through creation of reusable functions and modules
• Decompose long (80+ lines) components/functions into smaller ones. Keep in same file if single-use; split if file exceeds 200 lines
• Keep functions focused and under 50 lines when possible
• Avoid deep nesting (max 3 levels)
• Proper error handling with typed catch blocks

Library-First Approach

• ALWAYS search for existing solutions before writing custom code

- Check package registries for existing libraries - Evaluate existing services/SaaS solutions - Consider third-party APIs for common functionality

• Custom code IS justified when:

- Specific business logic unique to the domain - Performance-critical paths with special requirements - When external dependencies would be overkill - Security-sensitive code requiring full control

• Remember: Every line of custom code is a liability that needs maintenance, testing, and documentation

Architecture and Design

• Clean Architecture & DDD Principles:

- Follow domain-driven design and ubiquitous language - Separate domain entities from infrastructure concerns - Keep business logic independent of frameworks - Define use cases clearly and keep them isolated

• Naming Conventions:

- AVOID generic names: utils, helpers, common, shared - USE domain-specific names: OrderCalculator, UserAuthenticator, InvoiceGenerator - Follow bounded context naming patterns - Each module should have a single, clear purpose

• Separation of Concerns:

- Do NOT mix business logic with UI components - Keep database queries out of controllers - Maintain clear boundaries between contexts

Anti-Patterns to Avoid

• NIH (Not Invented Here) Syndrome: Don't build what already exists (auth, state management, form validation)
• Generic Naming: No utils.js with 50 unrelated functions, no helpers/misc.js as a dumping ground
• Poor Boundaries: Mixing business logic with UI, database queries in controllers, unclear separation of concerns

Tech Stack Coverage

Languages: TypeScript, JavaScript, Python, Go, Swift, Kotlin Frontend: React, Next.js, React Native, Flutter Backend: Node.js, Express, GraphQL, REST APIs Database: PostgreSQL, Prisma, NeonDB, Supabase DevOps: Docker, Kubernetes, Terraform, GitHub Actions Cloud: AWS, GCP, Azure

Validation Checklist

Before finalizing architecture:

• Requirements clearly understood
• Constraints identified
• Each decision has trade-off analysis
• Simpler alternatives considered
• ADRs written for significant decisions
• Team expertise matches chosen patterns
• Code follows Clean Architecture boundaries
• No premature optimization or over-engineering