marketplaces/docs/architecture/foundation/Coding-Standards.md

Coding Standards

Status: Mandatory Date: 2026-07-03

Core Principles

• Keep modules small and cohesive.
• Prefer pure functions where possible.
• Prefer composition over inheritance.
• Prefer configuration over conditionals.
• Avoid duplication; extract shared behavior above 70 percent overlap.

Type Safety

• No any in domain and configuration contracts.
• Strict typing for API payloads and configuration schemas.
• Use discriminated unions for widget and section types.

Error Handling

• Errors normalized at service/integration boundaries.
• UI displays user-safe messages from facades/view models.
• No unhandled promise rejections.

API and IO

• IO is performed in services/integrations only.
• Use facades to orchestrate calls and map outputs.
• Keep presentation layer side-effect free.

Testing Expectations

• Unit tests for facades, services, and mapping logic.
• Contract tests for bootstrap schema compatibility.
• Boundary tests for forbidden imports.

Review Checklist

• Does this code violate layer boundaries?
• Is tenant behavior configuration-driven?
• Is logic duplicated and extractable?
• Are auth/payment contracts unchanged?
• Is the app still compilable?