htc_3.1.swift

struct User {
    let id: AnyHashable
}
struct NewsState {
    var user: User
    var step: Step
}
extension NewsState {
    enum Step {
        case initial
        case loading
        case loaded(data: [String])
    }
}
enum NewsEvent {
    case dataLoaded(data: [String])
    case loadData
}
extension NewsState {
    static func reduce(state: NewsState, event: NewsEvent) -> NewsState {
        var state = state
        switch event {
        case .dataLoaded(let data):
            state.step = .loaded(data: data)
        case .loadData:
            state.step = .loading
        }
        return state
    }
}