zoukankan      html  css  js  c++  java
  • [RxJS] exhaustMap vs switchMap vs concatMap

    exhaustMap: It drop the outter observable, just return the inner observable, and it waits until previous observable complete before emit next observable.

    Good for canceling extra network outter request, for example click (outter) request trigger network (inner) request, if network (inner) request is not finished yet, new click (outter) request will be ignored.

    Use case: "Save" button, avoid send extra network request to the server.

    switchMap: Map to inner observable, cancel previous request.

      // exhaustMap
    
      @Effect()
      login$ = this.actions$
        .ofType(Auth.LOGIN)
        .map((action: Auth.Login) => action.payload)
        .exhaustMap((auth: Authenticate) =>
          this.authService
            .loginUser(auth.email, auth.password))
        .map(user => new Auth.LoginSuccess({user}))
        .catch(error => of(new Auth.LoginFailure(error)));
    
    
    // switchMap
    
      @Effect()
      login$ = this.actions$
        .ofType(Auth.LOGIN)
        .map((action: Auth.Login) => action.payload)
        .switchMap((auth: Authenticate) =>
          this.authService
            .loginUser(auth.email, auth.password)
            .map(user => new Auth.LoginSuccess({user}))
            .catch(error => of(new Auth.LoginFailure(error)));
         )
    .shareReplay(1)

    SwitchMap has cancelling logic.

    concatMap:

    Good for waiting previous network request finished. For example, We have a form, when use is typing, we also want to save the data, send to the server. 

    Every network request will send in order, and wait pervious network request finished.

  • 相关阅读:
    ncnn 编译配置
    Android 配置 ncnn
    Android Studio 配置 OpenCV4+
    ROS catkin cheat sheet
    CMake 使用代理服务器
    Git设置代理服务器
    安卓assets处理
    【Android】Toast on non-UI thread
    高级语言编译和运行系统
    linux环境安装包方式
  • 原文地址:https://www.cnblogs.com/Answer1215/p/7630433.html
Copyright © 2011-2022 走看看