Conditional chaining in angular 2

Question

I work in Angular 2 and I am making a series of asynchronous calls from a service. Some calls should be made conditionally only in my call chain. My initial call chain is as follows:

PSEUDO CODE

this.post().flatMap( () => this.put() ).flatMap( () => this.get() )..etc.

Then I need to conditionally attach additional asynchronous calls to my chain based on an array of variables.

I use this approach:

PSEUDO CODE

...flatMap( () => return this.additionalCallsFunction(callArray) )
.flatMap( () => this.finalPostRequest() ).subscribe(...)

additionalCallsFunction(callArray){
  if(callArray.length === 0) return Observable.empty()
  else { return this.get().concatMap( (res) => this.put(res).flatMap( () => { 
    callArray.removefirstItem()
    return this.additionalCallsFunction(callArray)
  }); 
}

Angular Observables, , . , , , , , , , . . .empty() .never(), .

/ !

Answer 1

, Observable.of(undefined) Observable.empty(). , Observable.empty() .

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