Hard Error Handling

Log Errors with doOnError

Create a Flux that emits 10, 20, 0, 30. Map each to 100/element. Use doOnError to print "Error: <message>" before recovering with onErrorReturn(-1). Subscribe and print.

Expected: 10, 5, Error: / by zero, -1

Expected

10
5
Error: / by zero
-1

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Main.kt

Log Errors with doOnError

hard⏱ 15 minkotlinreactorchallengeerror-handling

Create a Flux that emits 10, 20, 0, 30. Map each to 100/element. Use doOnError to print "Error: <message>" before recovering with onErrorReturn(-1). Subscribe and print.

Expected: 10, 5, Error: / by zero, -1

Why this works

doOnError() is a side-effect operator — it lets you perform an action (like logging) when an error occurs without consuming the error. The error continues downstream to be handled by onErrorReturn() or similar operators.

Expected output

10
5
Error: / by zero
-1

Log Errors with doOnError

Create a Flux that emits 10, 20, 0, 30. Map each to 100/element. Use doOnError to print "Error: <message>" before recovering with onErrorReturn(-1). Subscribe and print.

Expected: 10, 5, Error: / by zero, -1

Expected

10 5 Error: / by zero -1

Log Errors with doOnError

hard⏱ 15 minkotlinreactorchallengeerror-handling

Create a Flux that emits 10, 20, 0, 30. Map each to 100/element. Use doOnError to print "Error: <message>" before recovering with onErrorReturn(-1). Subscribe and print.

Expected: 10, 5, Error: / by zero, -1

Why this works

Expected output

10 5 Error: / by zero -1