A showcase of Remesh DSL

todo-app.remesh

domain TodoInputDomain {
  state TodoInput = ''

  command updateTodoInput(newTodoInput: string) {
    return TodoInput.new(newTodoInput)
  }
}

type Todo = {
  id: string
  content: string 
  completed: boolean
}

domain TodoListDomain {
  state TodoList = [] as Todo[]

  event AddTodoFailedEvent: {
    message: string
  }

  event AddTodoSuccessEvent: {
    todo: Todo
  }

  command addTodo(content: string) {
    if (content.length < 1) {
      return AddTodoFailedEvent({
        message: 'Todo content must be at least 1 character long'
      })
    }

    let todoList = TodoList.get()

    let todo = {
      id: uuid(),
      content,
      completed: false
    }
    

    return [
      AddTodoSuccessEvent({ todo }),
      TodoList.new(todoList.concat(todo))
    ]
  }
}


domain TodoHeader {
  domain todoInputDomain = TodoInputDomain.get()

  domain todoListDomain = TodoListDomain.get()

  query todoHeader() {
    return {
      todoInput: todoInputDomain.TodoInput.get(),
      todoList: todoListDomain.TodoList.get()
    }
  }

  command updateTodoInput = todoInputDomain.command.updateTodoInput

  command addTodo() {
    let content = todoInputDomain.TodoInput.get()
    return todoListDomain.command.addTodo(content)
  }

  command$ todoHeader() {
    return fromEvent(todoListDomain.event.AddTodoSuccessEvent)
      |> map(() => todoInputDomain.command.updateTodoInput(''))
  }
}