I don't see a channel dedicated to the kotlin-resu...

# arrow

[David Kubecka]

I don't see a channel dedicated to the kotlin-result library so allow me to ask here because kotlin-result is partly inspired by Arrow's Either so the problem might be similar in both frameworks.

In my controller, when I get a Result, I want to either throw an error in case of Err, or transform Ok. Is there a nicer way than this?

myResult
  .getOrThrow { createException() }
  .let { transform(it) }

I was thinking of something similar to mapBoth which, however, maps both Ok and Err to a common type.

[Youssef Shoaib [MOD]]

you're likely looking for a fold function. I'm not sure if kotlin-result provides it, but the implementation is likely trivial.

[raulraja]

https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/fold.html

[David Kubecka]

fold is the same as mapBoth and as I said I do want to throw an exception for the error case, not a result.

[Youssef Shoaib [MOD]]

Fold isn't the same though. It deconstructs the whole value, and so fold(transform) { throw createException() } will do the trick

[David Kubecka]

Well, in kotlin-result they are the same 🙂 https://github.com/michaelbull/kotlin-result/blob/master/kotlin-result/src/commonMain/kotlin/com/github/michaelbull/result/Map.kt#L127 Anyway, it turns out that I can indeed use this for my use case. I just must have made some silly mistake in trying so yesterday...