view model inputs and outputs

mvvm_rx_search_inputs_outputs.md

class SearchViewModel<T> {
    // inputs
    private let searchSubject = PublishSubject<String>()
    var searchObserver: AnyObserver<String> {
        return searchSubject.asObserver()
    }
     
    // outputs
    private let loadingSubject = PublishSubject<Bool>()
    var isLoading: Driver<Bool> {
        return loadingSubject
            .asDriver(onErrorJustReturn: false)
    }

    private let errorSubject = PublishSubject<SearchError?>()
    var error: Driver<SearchError?> {
        return errorSubject
            .asDriver(onErrorJustReturn: SearchError.unkowned)
    }

    private let contentSubject = PublishSubject<[T]>()
    var content: Driver<[T]> {
        return contentSubject
            .asDriver(onErrorJustReturn: [])
    }
}