角度 httpclient 返回一个 Observable

Question

private getScmServiceMeta(serviceId: string): Observable<any> {
    let service = this.getServiceItem(serviceId);

    if (service) {
        return this.httpClient.get(serviceUri).map((res: Response) => {
                return _.get(res, 'data.serviceinfo');
            })
    } else {
        return Observable.throw('backend server error');
    }
}

public inquireScmData(serviceId: string, params: object, templateId: string): Observable<any> {
    return this.getScmServiceMeta(serviceId).map((serviceInfo: any) => {

        let uri = serviceInfo.routeTemplate;

        // How to return the _.get(res, 'data') as an Observable ???
        return this.httpClient.get(uri).map((res: Response) => {
            if (_.startsWith(_.get(res, 'status.code'), '200')) {
                return _.get(res, 'data');
            } else {
                throw ('status code error');
            }
        })
    })
}

如上代码，调用inquireScmData函数时需要返回一个observable，但在函数内部，需要调用另一个异步函数getScmServiceMeta，也返回一个Observable，那么如何返回'_.get(res, 'data')' 作为 Observable ？？？ 谢谢

Answer 1

rxjs 在 Observable 上为您提供了一个静态方法来执行此操作。

Observable.of( _.get(res, 'data') );

不过，您将拥有一个Observable<Observable<Observable<any>>>。这是您的意图，还是您只想链接“异步”操作。如果是这样，您可能应该保留您的代码，并使用mergeMap。

public inquireScmData(serviceId: string, params: object, templateId: string): Observable<any> {
  return this.getScmServiceMeta(serviceId).mergMap((serviceInfo: any) => {

    let uri = serviceInfo.routeTemplate;

    return this.httpClient.get(uri).map((res: Response) => {
      if (_.startsWith(_.get(res, 'status.code'), '200')) {
        return _.get(res, 'data');
      } else {
        throw ('status code error');
      }
    })
  })
}