Reactive Programming in Kotlin

onErrorReturn – return a default value on error

The onErrorReturn provides you with a technique to specify a default value to return to the downstream in case an error occurred in the upstream. Take a look at the following code snippet:

    fun main(args: Array<String>) { 
      Observable.just(1,2,3,4,5) 
        .map { it/(3-it) } 
        .onErrorReturn { -1 }//(1) 
        .subscribe { 
           println("Received $it") 
        } 
    }

We used the onErrorReturn operator to return -1 whenever an error occurs. The output is as follows:

As we can see in the output, the onErrorReturn operator returns the specified default value. The downstream didn't receive any item further as the upstream stopped ...