NestJS CQRS Hexagonal Architecture Schematic

A powerful Angular CLI schematic for generating CQRS (Command Query Responsibility Segregation) modules following hexagonal architecture principles in NestJS applications.

Features

• 🏗️ Complete CQRS Structure: Generates commands, queries, handlers, and controllers
• 🔷 Hexagonal Architecture: Follows clean architecture principles with clear separation of concerns
• 🗄️ TypeORM Integration: Includes repository pattern with TypeORM entities
• 📝 TypeScript Support: Fully typed with proper interfaces and DTOs
• 🔧 Module Registration: Automatically registers the generated module in the parent module
• ✅ Validation: Input validation using Zod schemas
• 🎯 Best Practices: Follows NestJS and clean architecture best practices

Installation

npm install -D @lcasass3/nest-schematics

Usage

Basic Usage

# Generate a CQRS module for a "user" entity
nest g -c @lcasass3/nest-schematics cqrs-module user

# Generate in a specific path
nest g -c @lcasass3/nest-schematics cqrs-module user --path=src/modules

# Specify parent module for registration
nest g -c @lcasass3/nest-schematics cqrs-module user --module=src/app.module.ts

Options

Generated Structure

When you run the schematic with schematics @lcasass3/nest-schematics:cqrs-module user, it generates:

src/user/
├── user.module.ts                              # Main module file
├── application/
│   ├── commands/
│   │   ├── handlers/
│   │   │   ├── create-user.handler.ts          # Create command handler
│   │   │   ├── update-user.handler.ts          # Update command handler
│   │   │   ├── delete-user.handler.ts          # Delete command handler
│   │   │   └── index.ts                        # Barrel export
│   │   └── impl/
│   │       ├── create-user.command.ts          # Create command
│   │       ├── update-user.command.ts          # Update command
│   │       ├── delete-user.command.ts          # Delete command
│   │       └── index.ts                        # Barrel export
│   └── queries/
│       ├── handlers/
│       │   ├── all-users.handler.ts            # Get all query handler
│       │   ├── find-user-by-id.handler.ts      # Find by ID query handler
│       │   └── index.ts                        # Barrel export
│       └── impl/
│           ├── all-users.query.ts              # Get all query
│           ├── find-user-by-id.query.ts        # Find by ID query
│           └── index.ts                        # Barrel export
├── domain/
│   ├── entities/
│   │   ├── user.entity.ts                      # Domain entity
│   │   └── index.ts                            # Barrel export
│   ├── repositories/
│   │   ├── users.repository.ts                 # Repository interface
│   │   └── index.ts                            # Barrel export
│   └── dtos/
│       ├── create-user.dto.ts                  # Create DTO with validation
│       ├── update-user.dto.ts                  # Update DTO with validation
│       └── index.ts                            # Barrel export
└── infrastructure/
    ├── users.controller.ts                     # REST controller
    └── persistance/
        ├── entities/
        │   ├── user.typeorm-entity.ts          # TypeORM entity
        │   └── index.ts                        # Barrel export
        ├── repositories/
        │   ├── users.typeorm-repository.ts     # TypeORM repository
        │   └── index.ts                        # Barrel export
        └── modules/
            ├── typeorm-user.module.ts          # TypeORM module
            └── index.ts                        # Barrel export

Architecture Overview

Hexagonal Architecture Layers

1. Domain Layer (domain/): Contains business logic, entities, and repository interfaces
2. Application Layer (application/): Contains use cases (commands, queries, and handlers)
3. Infrastructure Layer (infrastructure/): Contains external concerns (controllers, database, etc.)

CQRS Pattern

• Commands: Handle write operations (create, update, delete)
• Queries: Handle read operations (find, get all)
• Handlers: Process commands and queries
• DTOs: Data transfer objects with validation

Dependencies

The schematic will check for and warn about missing dependencies:

• @nestjs/common
• @nestjs/core
• @nestjs/cqrs
• @nestjs/typeorm
• typeorm

Development

Building the Schematic

# Install dependencies
npm install

# Build
npm run build

# Build in watch mode
npm run build:watch

Code Quality Features

• ✅ Validation: Comprehensive input validation and error handling
• 🔍 Smart Module Detection: Automatically finds the appropriate parent module
• 🚫 Duplicate Prevention: Prevents duplicate imports and module registrations
• 📝 Clear Logging: Informative console output for debugging
• 🏗️ Modular Design: Well-organized utility classes for maintainability

License

MIT

Support

For issues and questions, please open an issue on the GitHub repository.