RxSwift

1<Observable>.shareReplay(bufferSize) 表示可以把以前处理过的信号回放出去，不用重复处理信号

let mapO = Observable.just(10).map({ (number) -> Int in
            print("MAP")
            return number
        }).shareReplay(1)
        
        mapO.subscribeNext { (number) in
            print(number)
        }
        
        mapO.subscribeNext { (number) in
            print(number+1)
        }

比如以上代码，加了shareReplay(1)之后，订阅了两次信号只会进行一次Map操作

2. 使用RxMoya框架时，如果viewModel的属性里初始化直接创建了请求provider,在init方法中

class DynamicViewModel: DataSource {
    var refreshDriver = PublishSubject<Void>()
    var items: [DynamicModel] = [DynamicModel]()
    let results: Driver<[DynamicModel]>
    var dynamicProvider = RxMoyaProvider<NetWorkService>()
    
    init(dynamicProvider: RxMoyaProvider<NetWorkService>) {
//这种情况下会出现未初始化变量而先使用该变量的错误
//         results = refreshDriver.startWith(()).flatMapLatest {
//            self.dynamicProvider.request(NetWorkService.User(a: .GetDynamics(user: "2390")))
//         }.mapResponseToObjArray(DynamicModel).catchErrorJustReturn([]).asDriver(onErrorJustReturn: [])
//这种情况下就正常，所以建议在init方法中就要传入provider
        results = refreshDriver.startWith(())
            .flatMapLatest {
                dynamicProvider.request(.User(a: .GetDynamics(user: "2390")))
                    .retry(3)
                    .observeOn(MainScheduler.instance)
            }
            .mapResponseToObjArray(DynamicModel)
            .catchErrorJustReturn([])
            .asDriver(onErrorJustReturn: [])
    }
}