Question

我想订阅多个可观察变量，但是第二个可观察变量取决于第一个。因此，从第一个开始，我得到了一个客户ID，我需要从一个新的可观察对象中获取所有信息。

this.taskService
      .get(this.$state.params.taskId)
      .pipe(
        switchMap((taskDetails: IGetTask) => this.taskService.getAgreement(taskDetails.taskParameters.customerAgreementId)),
        tap(customerAgreement => this.customerAgreement = customerAgreement)
      )
      .subscribe((data: any) => {
        this.signees = new SignatoryDetails(data);
        this.customerDetails = new CustomerDetails(data);
      });

这是我当前的代码，但我不知道如何继续添加新观察者以获取客户信息。客户ID存在于this.customerAgreement中。我可以通过this.customerService.getCustomer（ID）获取客户信息。

Answer 1

为什么不只是switchMap？您同时需要客户协议和客户信息吗？然后，您应该使用map将第一个可观察到的结果映射到第二个可观察到的结果。

这里是一个例子：

this.taskService
    .get(this.$state.params.taskId)
    .pipe(
        switchMap((taskDetails: IGetTask) => this.taskService.getAgreement(taskDetails.taskParameters.customerAgreementId)),
        tap(customerAgreement => this.customerAgreement = customerAgreement),
        switchMap(customerAgreement => this.customerService.getCustomer(customerAgreement.id).pipe(
            map(customerInformation => ({customerInformation: customerInformation, customerAgreement: customerAgreement}))))
    )
    .subscribe((data: any) => {
        let customerAgreement = data.customerAgreement;
        let customerInformation = data.customerInformation;

        this.signees = new SignatoryDetails(data);
        this.customerDetails = new CustomerDetails(data);
    });

Answer 2

您需要在switchMap中将输入与输出压缩在一起：

switchMap((taskDetails: IGetTask) =>
        Observable.zip(this.taskService.getAgreement(taskDetails.taskParameters.customerAgreementId),
                        Observable.Of(taskDetails.taskParameters.customerAgreementId)))

订阅多个可观察物

2 个答案: