Reactive Programming in Kotlin

The error handling operators

We already learned about the onError event in the Subscriber/Observer. However, the problem with the onError event is that the error is emitted to the downstream consumer chain, and the subscription is terminated instantly. For example, take a look at the following program:

    fun main(args: Array<String>) { 
      Observable.just(1,2,3,5,6,7,"Errr",8,9,10) 
       .map { it.toIntOrError() } 
       .subscribeBy ( 
           onNext = { 
              println("Next $it") 
           }, 
           onError = { 
              println("Error $it") 
           } 
        ) 
     } 

The output of the program is shown in the following screenshot:

The program throws an exception in the map operator when the string Errr is emitted from ...