Cómo aplicar DDD y arquitectura hexagonal en NestJS con un ejemplo práctico

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Un servicio NestJS que empieza con controladores y llamadas directas a Prisma se vuelve difícil de cambiar cuando aparecen reglas de negocio como asignación de técnicos o tareas obligatorias. El artículo propone usar Domain-Driven Design para expresar ese comportamiento y la arquitectura hexagonal para controlar las dependencias. Como ejemplo, desarrolla una API de gestión de servicios con TypeScript, NestJS, Prisma y PostgreSQL, organizada en dos módulos: órdenes de servicio y visitas. Las reglas incluyen prioridades según el nivel de servicio, finalización condicionada a actividades completadas y programación de visitas sin solapamientos. El código completo está disponible en GitHub como implementación educativa.

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