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 the Observable. The exception was caught by the onError handler, but the Subscription doesn't get any further emissions.

This may not be the desired behavior every time. Although we cannot pretend the error never happened and continue...