打字稿方法返回未定义？

Question

您好，我有一个 angular 5 应用程序。我有一个 returns undefined 的服务方法。这就是我想要做的。我有一个名为 cloneFlight 的函数。我正在调用 flightsService.getCampaignsToClone(this.flight) 这是 returning 值未定义。

cloneFlight() {
    combineLatest(
      this.translateService.get('CONFIRM.CLONE_FLIGHT', { item: this.flight.name}),
      this.flightsService.getCampaignsToClone(this.flight)
    ).subscribe( ([header, campaigns]) => { 
      this.cloneFlightService.openModal(header,this.flight,campaigns);
    });
  }

getCampaignsToClone 的代码如下

 getCampaignsToClone(flight: Flight){

    let campaignStatusesIdArr: string[];
    let campaigns: CampaignUnpaginated[] ; 
    this.campaignService.getStatuses().subscribe(
      (data) => { 
        campaignStatusesIdArr = data.filter( x => x.code === (CampaignStatusCode.IN_PROGRESS || 
          CampaignStatusCode.READY)).map( y => y.id);
      }
    );
    let accountId: string = flight.campaign.account.id;    

    this.campaignService.getUnpaginatedCampaigns(
      {
        statuses: campaignStatusesIdArr,
        accounts: accountId
      }
    ).subscribe(data=>{
      console.log(data);
      campaigns = data;
    });
    return Observable.of(campaigns);
  }

在 getCampaignsToClone 中，我正在进行 campaignService.getStatuses() returns Observable 的 http 调用。然后过滤掉其中的一些然后我打电话给 getUnpaginatedCampaigns 这是另一个 http 调用。 anyidea 什么是编写此代码的最佳方法，以便该方法不会 return 未定义。我想我可能没有使用 rxjs 运算符。有人可以帮我弄清楚吗？

非常感谢

Answer 1

重写您的 getCampaignsToClone 方法，使其 returns 成为一个 Observable 序列。使用flatMap依次订阅getUnpaginatedCampaigns observable

getCampaignsToClone(flight: Flight): Observable<CampaignUnpaginated[]> {
 return this.campaignService.getStatuses().pipe(
    map(data => data.filter( x => x.code === (CampaignStatusCode.IN_PROGRESS || CampaignStatusCode.READY)).map(x => x.id)),
    flatMap(ids => this.campaignService.getUnpaginatedCampaigns({
        statuses: ids,
        accounts: flight.campaign.account.id,
    }))
  );
}

打字稿方法返回未定义？

typescript method returning undefined?

typescript

rxjs5

rxjs-pipeable-operators