standard-use-case-architecture-patterns

Standard: Use Case Architecture Patterns

This standard defines how to structure use cases in the Packmind monorepo following hexagonal architecture principles. Use cases represent the entry points to domain logic and must follow consistent p... :

• Accept commands as single parameters in adapter methods rather than multiple individual parameters to ensure consistency and easier parameter additions
• Define each use case contract in its own file at packages/types/src/{domain}/contracts/{UseCaseName}.ts with Command type, Response type, and UseCase interface exports
• Export exactly three type definitions from each use case contract file: {Name}Command for input parameters, {Name}Response for return value, and I{Name}UseCase as the interface combining both
• Extend AbstractAdminUseCase and implement executeForAdmins method for use cases requiring admin privileges, with automatic validation that the user is a member with admin role
• Extend AbstractMemberUseCase and implement executeForMembers method for organization-scoped use cases that do NOT operate within a specific space, with automatic user and organization validation
• Extend AbstractSpaceMemberUseCase and implement executeForSpaceMembers method for use cases operating within a specific space (command includes spaceId), with automatic user, organization, and space membership validation
• Extend PackmindCommand for authenticated use case commands that include userId and organizationId, or extend PublicPackmindCommand for public endpoints without authentication
• Extend SpaceMemberCommand instead of PackmindCommand for use case commands that include a spaceId to get both organizationId and spaceId typing
• Implement IPublicUseCase interface directly with an execute method for public use cases that don't require authentication, without extending any abstract use case class
• Never directly call Repositories in Adapter classes, repos must be called from Use Cases
• Never spread commands as multiple arguments in hexagon or UseCase classes; always pass the complete command object to maintain type safety and reduce errors
• Response and Commands must not be defined in the same file than the associated UseCase class
• Restrict use case classes to expose only the execute method for public use cases or executeForMembers/executeForAdmins methods for member/admin use cases, with no other public methods
• Reuse existing use cases through port/adapter interfaces instead of instantiating them directly within use cases
• UseCase must be associated with a Command and Response type

Full standard is available here for further request: Use Case Architecture Patterns