@ddd-master/command-bus package

The @ddd-master/command-bus package is a TypeScript library that provides an implementation of the command bus pattern for Domain-Driven Design (DDD) applications. It allows you to execute commands and perform actions in a centralized and decoupled manner.

Installation

You can install the @ddd-master/command-bus package using npm:

npm install @ddd-master/command-bus

Usage

To use the @ddd-master/command-bus package, you need to define your commands and command handlers.

Defining Commands

Commands represent actions or requests for changes in the system. You can define a command by implementing the ICommand interface. For example:

export interface ICreateUserCommand extends ICommand {
  email: string;
  password: string;
}

export class CreateUserCommand implements ICreateUserCommand {
  public readonly email: string;
  public readonly password: string;

  public constructor({ email, password }: ICreateUserCommand) {
    this.email = email;
    this.password = password;
  }
}

Defining Command Handlers

Command handlers are responsible for executing commands and performing the necessary actions. You can implement the ICommandHandler interface to define your command handlers. For example:

export class CreateUserCommandHandler implements ICommandHandler<ICreateUserCommand, CreateUserCommandHandlerResult> {
  private readonly userRepository: UserRepository;
  public constructor({ userRepository }: Dependencies) {
    this.userRepository = userRepository;
  }

  public handle(command: ICommand): CreateUserCommandHandlerResult {
    const { email, password } = command as ICreateUserCommand;

    const createdUser: User = { email, password };

    this.userRepository.save({ user: createdUser });

    return { email, password };
  }
}

Registering Command Handlers

Once you have your command handlers, you need to register them with the command bus. For example:

const commandBus = new CommandBus();
const createUserCommandHandler = new CreateUserCommandHandler();
commandBus.register(CreateUserCommand, createUserCommandHandler);

Executing Commands

To execute a command, you can use the execute method of the command bus. For example:

const result = commandBus.execute<ICreateUserCommand, CreateUserCommandHandlerResult>(
  new CreateUserCommand({ email: '[email protected]', password: '123456' }),
);

const { email, password } = result;
console.log(email, password);

The execute method returns the result of the command handler. You can access the result and process it accordingly.

Contributing

Contributions to the @ddd-master/command-bus package are welcome! Feel free to open issues or submit pull requests on the GitHub repository. Please follow the code of conduct when contributing.

License

The @ddd-master/command-bus package is open-source software licensed under the MIT License.