Gem Track Backend Starter

This repository is scaffolded as a production-ready modular monolith using:

• Node.js
• TypeScript
• Express
• TypeORM
• TSOA
• Swagger UI

Architecture Goals

• Clean Architecture + Domain Driven Design
• Strict separation of domain, application, infrastructure, and interfaces
• Multi-tenant SaaS readiness
• Scalability through bounded contexts
• Swagger/OpenAPI documentation via TSOA

Folder Structure

src/
  bootstrap/                         # Composition root and dependency wiring
  main.ts                            # Process startup and graceful shutdown
  app.ts                             # Express application assembly

  shared/
    domain/                          # Pure business abstractions
    application/                     # Cross-cutting use-case ports/contracts
    infrastructure/                  # DB, security, logging, config, messaging
    interfaces/http/                 # Middleware, presenters, TSOA, Swagger

  modules/
    tenancy/
      domain/                        # Aggregate, repository contract, events
      application/                   # Commands, queries, DTOs, handlers
      infrastructure/                # TypeORM entity, mapper, repository impl
      interfaces/http/controllers/   # TSOA controllers

  types/                             # Framework type augmentation

Dependency Flow

Dependencies always point inward:

interfaces -> application -> domain

infrastructure implements ports defined by application or contracts defined by domain.

Rules:

• domain does not import Express, TSOA, TypeORM, or database code.
• application orchestrates use cases and depends only on domain contracts and abstract ports.
• interfaces is transport-only and should never hold business rules.
• repositories return domain aggregates, not ORM entities.
• TypeORM entities stay in infrastructure and are mapped to/from domain aggregates.

Multi-Tenant Strategy

The scaffold is built around a tenant-aware request context:

• tenant.middleware resolves tenant from headers, subdomain, or request metadata.
• TenantContext flows from the HTTP edge into application and infrastructure.
• tenant-data-source.resolver.ts centralizes tenancy-aware database access.
• Shared-schema is the default mode, but the resolver is intentionally shaped so you can grow into schema-per-tenant or database-per-tenant.

Swagger

Swagger is exposed from:

• GET /docs
• GET /swagger.json

TSOA controller decorators are used for OpenAPI generation, and the generated artifacts are written to:

• src/shared/interfaces/http/tsoa/generated/routes.ts
• src/shared/interfaces/http/tsoa/generated/swagger.json

The repository also includes starter generated files so the scaffold is understandable before running code generation.

Sample Module

The included tenancy bounded context demonstrates:

• Domain aggregate with business invariants
• Application command/query handlers
• Repository contract in the domain layer
• TypeORM repository implementation in infrastructure
• TSOA controller in interfaces

Suggested Next Steps

1. Install dependencies with npm install.
2. Generate TSOA artifacts with npm run tsoa:spec && npm run tsoa:routes.
3. Extend modules/ with bounded contexts such as identity-access, catalog, billing, and orders.
4. Add migrations, outbox processing, authentication policies, and integration tests.