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Modules

Modules are a powerful way to organize and structure your dependency injection setup in NexusDI. They allow you to group related services, providers, and configuration into logical units. Think of them as guild departments - each handles its own specialty, but they all contribute to the guild's success.

For a complete guide to creating and using modules, see Module Basics.

What are Modules?​

A module is a class decorated with @Module() that defines a collection of:

  • Services - Classes that provide functionality
  • Providers - Dependencies that can be injected
  • Imports - Other modules to include
  • Exports - Services/providers to make available to other modules

Basic Module Example​

import { Module, Service, Token, Inject } from '@nexusdi/core';

// Define tokens
export const USER_SERVICE = new Token<IUserService>('USER_SERVICE');
export const DATABASE = new Token<IDatabase>('DATABASE');

// Define services
@Service(USER_SERVICE)
class UserService implements IUserService {
  constructor(@Inject(DATABASE) private db: IDatabase) {}

  async getUser(id: string) {
    return this.db.query(`SELECT * FROM users WHERE id = ?`, [id]);
  }
}

// Create the module
@Module({
  providers: [UserService],
  providers: [{ token: DATABASE, useClass: PostgresDatabase }],
})
export class UserModule {}

Module Registration​

import { Nexus } from '@nexusdi/core';
import { UserModule } from './modules/user.module';

const container = new Nexus();
container.set(UserModule);

Benefits of Modules​

  • Organization: Group related services and providers into logical units
  • Reusability: Share modules across different applications
  • Testing: Easily mock and test specific parts of your application
  • Configuration: Encapsulate environment-specific settings
  • Composability: Import and combine modules as needed

For detailed explanations of these benefits and advanced patterns, see Module Basics and Module Patterns.

Next Steps​