What are dependency injection approaches for Combine in Swift?

In Swift, dependency injection is a design pattern that allows you to provide your classes with their dependencies from the outside. When combined with Apple's Combine framework, this can lead to more testable and modular code. Below are some common approaches to implement dependency injection in a Combine-based application.

Example of Dependency Injection in Combine


            // Define a protocol for a service
            protocol DataService {
                func fetchData() -> AnyPublisher
            }

            // Create a concrete implementation of the DataService
            class ApiService: DataService {
                func fetchData() -> AnyPublisher {
                    // Implement API call using Combine
                    return URLSession.shared.dataTaskPublisher(for: URL(string: "https://api.example.com/data")!)
                        .map { $0.data }
                        .receive(on: DispatchQueue.main)
                        .eraseToAnyPublisher()
                }
            }

            // ViewModel that requires a DataService
            class ViewModel {
                private let dataService: DataService
                @Published var data: Data?
                @Published var error: Error?

                init(dataService: DataService) {
                    self.dataService = dataService
                }

                func loadData() {
                    dataService.fetchData()
                        .sink(receiveCompletion: { completion in
                            if case let .failure(err) = completion {
                                self.error = err
                            }
                        }, receiveValue: { data in
                            self.data = data
                        })
                        .store(in: &cancellables)
                }

                private var cancellables = Set()
            }

            // Usage in a view
            let viewModel = ViewModel(dataService: ApiService())
            viewModel.loadData()

What are dependency injection approaches for Combine in Swift?

Example of Dependency Injection in Combine

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What are dependency injection approaches for Combine in Swift?

Example of Dependency Injection in Combine

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