RxJS mergeMap 等待内部 Observables

Question

我有一个解决方案，起初似乎有效，但后来我在慢速网络下尝试了它：

public getKeyFigureValuesForAllClients(keyFigurename: string) {

    const keyFigureDefintion$ = this.keyFigureDefintions$.pipe(
      flatMap((keyFigure) => keyFigure),
      filter((x) => x.name === keyFigurename),
      take(1));

    const clients$ = this.dataService.getClients().pipe(
      flatMap((client) => client));

    const keyFigureAndClients$ = combineLatest([keyFigureDefintion$, clients$]);
    return keyFigureAndClients$.pipe(
      tap(x=>console.log(x)),
      switchMap(([keyfigure, client]) =>

        this.dataService.getDataPointsByPeriodName(client.id, this.currentPeriodName).pipe(
          map((datapoints) => ({
              client,
              datapoints,
              keyFigureCalculator: new KeyFigureCalculator(keyfigure, datapoints),
            }),
          )),
      ),
      tap(x=>console.log(x)),
      toArray(),
    );
  }

所以首先我加载我的关键人物和客户列表。然后我想得到相应的数据点和 return 一个包含我所有值的数组。但似乎 this.dataService.getDataPointsByPeriodName() 需要更长的时间，所以我只得到第一个客户的值。如果我在 Chrome 中将网络速度更改为“在线”，一切正常（10 次尝试中有 9 次...）。

有等待接线员吗？我找到了一些关于 concatAll() 的信息，但我不知道将它放在哪里以及如何让它工作。

Answer 1

老实说，这有点奇怪，您将客户端流“只是”扁平化以便稍后再次使用 toArray()。也许这种方法的某个地方是所描述行为的原因，但我不能肯定地说。请在下面找到没有 flatMap

的建议

public getKeyFigureValuesForAllClients(keyFigurename: string) {

    const keyFigureDefintion$ = this.keyFigureDefintions$.pipe(
      map(keyFigures => keyFigures.find(keyFigure => keyFigure.name === keyFigurename)),
    )
    const clients$ = this.dataService.getClients();

    const keyFigureAndClients$ = forkJoin([keyFigureDefintion$, clients$]).pipe(    
      switchMap(([keyfigure, clients]) => {       
        return forkJoin(clients.map(client => this.dataService.getDataPointsByPeriodName(client.id, this.currentPeriodName).pipe(
          map((datapoints) => ({
              client,
              datapoints,
              keyFigureCalculator: new KeyFigureCalculator(keyfigure, datapoints),
            }),
          ))));
      }),
    );
  }

RxJS mergeMap 等待内部 Observables

RxJS mergeMap wait for inner Observables

observable

rxjs

angular