RxJs：您能将运算符作为参数传播到管道运算符中吗

我有两个可观察的流，它们执行非常独立的映射逻辑，但最终以以下3个运算符结束：

  this.selection
    .pipe(
      ..Custom mapping operators
      tap(_ => this.devicesLoading = true),
      switchMap(d => this.mapService.findLocationForDevices(d)),
      map(loc => marker([loc.latitude, loc.longitude])
    )
    .subscribe(markers => this.plotMarkers(markers));

我想将最后一个

点击、开关映射、映射

操作符移动到一个公共函数，这样我就可以在两个可观察的流中应用它们

我想做：

  private resolveLocationsAndConvertToMarkers = (devices: String[]) => [
    tap(_ => this.devicesLoading = true),
    switchMap((devices: string[]) => this.mapService.findLocationForDevices(devices)),
    map(loc => marker([loc.latitude, loc.longitude])
  ];

但我不确定如何将这些运算符扩展到管道参数中，例如：#

---

此错误提示

不存在期望3个或5个参数的重载。
您可以尝试使用本机
.apply（）

或者将操作符列表包装在
pipe（）中

或返回高阶函数

private resolveLocationsAndConvertToMarkers = (devices: String[]) => source=>source.pipe(
        tap(_ => this.devicesLoading = true),
        switchMap((devices: string[]) => this.mapService.findLocationForDevices(devices)),
        map(loc => marker([loc.latitude, loc.longitude])
      );

您可以尝试一种反应性方法（除非真正隔离，否则没有副作用）：

const preSelection$=this.selection
管
//..自定义映射运算符
();
常量选择$：可观察=预选$.pipe(
开关映射（预选=>
海螺(
of（null），
管道的（预选）(
switchMap（d=>this.mapService.findLocationForDevices（d）），
地图（位置=>标记（[位置纬度，位置经度]）
)
)
),
shareReplay（{bufferSize:1，refCount:true}）
);
const isLoading$：Observable=selection$.pipe（映射（x=>！！x））；
const sideEffectUpdatePlotMarkers$=selection$.pipe(
轻触（标记=>this.plotMarkers（标记））
);
//尽可能隔离'subscribe'呼叫和副作用
sideEffectUpdatePlotMarkers$.subscribe（）；
太好了，谢谢你，所有这些都奏效了。为了简单起见，我选择了中间选项。
this.selection
    .pipe.apply(null,this.resolveLocationsAndConvertToMarkers)

  private resolveLocationsAndConvertToMarkers = (devices: String[]) => pipe(
    tap(_ => this.devicesLoading = true),
    switchMap((devices: string[]) => this.mapService.findLocationForDevices(devices)),
    map(loc => marker([loc.latitude, loc.longitude])
  );

private resolveLocationsAndConvertToMarkers = (devices: String[]) => source=>source.pipe(
        tap(_ => this.devicesLoading = true),
        switchMap((devices: string[]) => this.mapService.findLocationForDevices(devices)),
        map(loc => marker([loc.latitude, loc.longitude])
      );

const preSelection$ = this.selection
  .pipe
  //..Custom mapping operators
  ();

const selection$: Observable<Marker> = preSelection$.pipe(
  switchMap(preSelection =>
    concat(
      of(null),
      of(preSelection).pipe(
        switchMap(d => this.mapService.findLocationForDevices(d)),
        map(loc => marker([loc.latitude, loc.longitude]))
      )
    )
  ),
  shareReplay({ bufferSize: 1, refCount: true })
);

const isLoading$: Observable<boolean> = selection$.pipe(map(x => !!x));

const sideEffectUpdatePlotMarkers$ = selection$.pipe(
  tap(markers => this.plotMarkers(markers))
);

// isolate `subscribe` calls and side effects as much as possible
sideEffectUpdatePlotMarkers$.subscribe();