Domain-Driven Design Strategic DDD Tactical DDD (TypeScript) Entity Value Object Domain Event Repository (Port) Application Service DDD Building Blocks | Building Block | Purpose | Identity? | Mutable? | |---------------|---------|-----------|----------| | Entity | Domain object with identity | Yes (ID) | Yes | | Value Object | Immutable descriptor | No (structural equality) | No | | Aggregate | Consistency boundary | Root entity has ID | Yes (via root) | | Domain Event | Something that happened | Event ID | No | | Repository | Persistence abstraction | N/A | N/A | | Domain Service | Logic no…