Clean Architecture SwiftUI Combine.swift

import Foundation
import SwiftUI
import Combine

// MARK: - Presentation Layer

struct MyView: View {
    @ObservedObject var viewModel: MyViewModel
    
    var body: some View {
        Text(viewModel.data)
    }
}

// MARK: - Domain Layer

class MyViewModel: ObservableObject {
    @Published var data: String = "say my name"
    
    func fetchData() {
        // Fetch data from the network or a local database
        // using the data access layer
    }
}

// MARK: - Data Access Layer

protocol DataFetcher {
    func fetchData() -> AnyPublisher<String, Error>
}

class NetworkDataFetcher: DataFetcher {
    func fetchData() -> AnyPublisher<String, Error> {
        // Fetch data from the network and call the completion handler
        Just("Hello")
            .setFailureType(to: Error.self)
            .eraseToAnyPublisher()
    }
}

class DatabaseDataFetcher: DataFetcher {
    func fetchData() -> AnyPublisher<String, Error> {
        // Fetch data from the local database and call the completion handler
        Just("Mom")
            .setFailureType(to: Error.self)
            .eraseToAnyPublisher() 
    }
}