RepositoryViewModel-Coordinator.swift

protocol RepositoryViewModelType: Transitionable //Make our view model Transitionable {
    
    var repositorySubject: PublishSubject<Repository> { get }
    
    func fetchRepositories(for observableText: Observable<String>) -> Driver<Result<[Repository]>>
}

class RepositoryViewModel : RepositoryViewModelType {
    
    fileprivate let disposeBag = DisposeBag()
    var repositorySubject = PublishSubject<Repository>()//add repositorySubject to recive the repositories selected
    weak var navigationCoordinator: CoordinatorType? //add navigationCoordinator property this is a protocol and weak to avoid retain cycles.
    
    init() {
        //subscribe to repositories change
        repositorySubject
            .asObservable()
            .subscribe(onNext: { [unowned self] in
                self.navigationCoordinator?.performTransition(transition: .showRepository($0)) //perform the transition
            })
            .addDisposableTo(disposeBag)
    }
    
    func fetchRepositories(for observableText: Observable<String>) -> Driver<Result<[Repository]>> {
        return RepositoryNetworking
            .fetchRepositories(for: observableText)
    }
}