RXJS 有条件地调用 observable

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();

从上面的代码我想实现以下场景

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 代码来看，它总是去更新方法，它没有考虑 this.shippingTabModified

的值

Answer 1

为什么不直接使用


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

obs$.subscribe();

编辑

条件调用：

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

Answer 2

您可以利用 concat 函数并执行类似这样的操作

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

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

干杯

RXJS 有条件地调用 observable

RXJS conditionally call observable

angular

rxjs

angular2-observables

iif