RXJS有条件地致电可观察到

Question

  const observable$ = iif(() => this.shippingTabModified,
      //Shipping Tab Modified True
      of(this.updateShippingInfo())
        .pipe(),
      //IF Shipping Tab Not Modified    
      of(this.shippingInfoService.getShipmentInfoByCardIdObservable(this.data.CardId))
        .pipe()
    )

    observable$.subscribe();

从上面的代码中，我想实现以下方案

if(foo === true)
{
  updatemethod()
}
// if foo is true and update method is executed we need to wait until update method is finished then go to second method

// If foo is false we can call second method without waiting
secondmethod();

，但是从我上面写的RXJS代码中，它总是转到更新方法，它不是考虑this.shippingtabmodified的值。

Answer 1

您可以利用concat功能，然后做类似的

const observables$ = condition ? [obs$1, obs$2] : [obs$2];

concat(...observables$).subscribe();

事情

Answer 2

为什么不只是使用

const obs$ = this.shippingTabModified ? 
  of(this.updateShippingInfo()) : 
  this.shippingInfoService.getShipmentInfoByCardIdObservable(this.data.CardId);

obs$.subscribe();

编辑

在条件下致电：

const obs$ = of(this.updateShippingInfo()).pipe(
  switchMap(res => this.shippingTabModified ?
    of(res) :
    this
      .shippingInfoService
      .getShipmentInfoByCardIdObservable(this.data.CardId)
)