SwiftUI: How to properly implement a paginated API call with infinite scrolling and state management?
Could someone explain I'm relatively new to this, so bear with me. I'm currently building a SwiftUI application that fetches paginated data from a REST API using `URLSession`. I want to implement an infinite scrolling feature, but I'm struggling to efficiently manage the state as new data is loaded. When I scroll to the bottom of the list, I want to trigger another API call to fetch more results. However, I keep working with issues where the UI shows duplicated entries and sometimes fails to load new data altogether. I have a model that represents each item and a view model that handles the data fetching. Here's my current implementation: ```swift import SwiftUI import Combine struct Item: Identifiable, Codable { let id: Int let title: String } class ItemsViewModel: ObservableObject { @Published var items: [Item] = [] private var currentPage = 1 private var isLoading = false private var cancellables = Set<AnyCancellable>() func fetchItems() { guard !isLoading else { return } isLoading = true let url = URL(string: "https://api.example.com/items?page=\(currentPage)")! URLSession.shared.dataTaskPublisher(for: url) .map { $0.data } .decode(type: [Item].self, decoder: JSONDecoder()) .sink(receiveCompletion: { completion in self.isLoading = false if case .failure(let behavior) = completion { print("behavior fetching items: \(behavior)") } }, receiveValue: { [weak self] newItems in self?.items.append(contentsOf: newItems) self?.currentPage += 1 }) .store(in: &cancellables) } } struct ItemsListView: View { @StateObject private var viewModel = ItemsViewModel() var body: some View { List(viewModel.items) { item in Text(item.title) } .onAppear { fetchMoreItemsIfNeeded() } } private func fetchMoreItemsIfNeeded() { if let lastItem = viewModel.items.last, lastItem.id == viewModel.items.count { viewModel.fetchItems() } } } ``` I attempted to prevent duplicated entries by checking the last item's ID against the current count of the items array, but this approach doesn't seem foolproof. Additionally, I noticed that sometimes the new fetch is triggered but returns an empty array, possibly due to the current page being incorrectly managed. What are the best practices for handling infinite scrolling in SwiftUI, especially regarding state management and preventing duplicate entries? How can I better manage pagination and ensure that my API calls are efficient? What's the best practice here? What would be the recommended way to handle this?