MVVM_RxSwift

MVVM Architecture pattern with RxSwift is fun when we fully utilize the power of RX

ViewControllerType

ViewControllerType, if we think about it we would want two mandatory functions, One is viewmodel variable and other is a func for binding the viewmodel

protocol ViewControllerType {
    associatedtype ViewModel: ViewModelType
    var viewModel: ViewModel! { get set}
    func bindViewModel()
}

ViewModelType

Basically, ViewModel's function is to receive input from Viewcontroller process the input and convert it into Output. We have taken fetching posts from network as an example

protocol ViewModelType {
    associatedtype Input
    associatedtype Output
    func transform(input: Input) -> Output
}

Segregating the problem

Now lets say we have a array of posts object to fetch from network or DB in future(We will implement Repository layer in Same Repo later). So There is a VC with a tableview that displays a list of posts that is fetched from network(for now).

Input and Output

Input and Output can be struct that contains Driver(Rx).

class PostsViewModel: ViewModelType {
    struct Input {
        let trigger: Driver<Void>
    }
    
    struct Output {
        let posts: Driver<[Post]>
    }
    
    func transform(input: Input) -> Output {
        let post = PostsDataManager.shared.getPosts()
        let postDriver = input.trigger.flatMapLatest{ _ in
            return post.asDriver(onErrorJustReturn: [])
        }
        return Output(posts: postDriver)
}

Feel free to dive into this simple code structure to understand the Usage