Invoicing SDK: Domain Layer

Core domain logic for the invoicing system following Domain-Driven Design (DDD) principles.

Overview

This package contains the pure business logic of the invoicing system, including:

• Entities: Core business objects like Invoice
• Value Objects: Immutable objects like Money, CustomerInfo, OrderItem
• Domain Services: Business logic that doesn't belong to a specific entity
• Domain Events: Events that represent important business occurrences
• Policies: Business rules and constraints
• Types: Shared type definitions

Features

• Pure domain logic with no external dependencies
• TypeScript-first with full type safety
• Domain events for decoupled communication
• Rich value objects for data integrity
• Comprehensive business rule validation

Installation

npm install @invoicing-sdk/domain
# or
pnpm add @invoicing-sdk/domain
# or
bun add @invoicing-sdk/domain

Usage

import { Invoice, Money, CustomerInfo } from '@invoicing-sdk/domain'

// Create value objects
const amount = new Money(100, 'EUR')
const customer = new CustomerInfo({
  name: 'John Doe',
  email: '[email protected]',
  address: '123 Main St'
})

// Work with domain entities
const invoice = new Invoice({
  customerId: 'customer-123',
  items: [/* order items */],
  // ... other properties
})

Architecture

This package follows Domain-Driven Design principles:

• Entity: Objects with identity that can change over time
• Value Object: Immutable objects defined by their attributes
• Domain Service: Stateless services that implement business logic
• Domain Event: Events that capture business-relevant occurrences
• Policy: Business rules and constraints

Development

# Build the package
pnpm build

# Watch for changes during development
pnpm dev

# Run tests
pnpm test

License

MIT