Mapping onError notifications

[twz123]

I often have the use case that I want to map the Throwable emitted by an onError notification of an Observable to something else, for example wrapping or unwrapping it.

Maybe I missed something, but apparently there is no stock solution in RxJava to achieve this. Currently, I use a custom Operator. Would it make sense to add such an Operator along with its corresponding Observable.mapError / Single.mapError methods to RxJava directly?

[akarnokd]

There is the onErrorReturn and onErrorResumeNext operators that will give you the Throwable which you can then map to a value or another error through Observable.error(), i.e.:

source.onErrorResumeNext(e -> Observable.error(e.getCause()))...

[davidmoten]

'materialize()' is useful in this regard too

On Wed, 27 Jan 2016 19:56 David Karnok [email protected] wrote:

There is the onErrorReturn and onErrorResumeNext operators that will give
you the Throwable which you can then map to a value or another error
through Observable.error(), i.e.:

source.onErrorResumeNext(e -> Observable.error(e.getCause()))...

—
Reply to this email directly or view it on GitHub
#3652 (comment).

[twz123]

Ah yeah, onErrorResumeNext is a bit more verbose, but does the trick, thanks! On the other hand, there's no onErrorResumeNext for Single, only onErrorReturn, which cannot be used for the described use case.

Would it then perhaps make sense to add an implementation of onErrorResumeNext to Single, too?

[artem-zinnatullin]

I'll add required operators for Single, first one is #3655, next one later.

@twz123 looks like your issue is now resolved? If so — please close it :)

[twz123]

Cool! onErrorResumeNext(Func1<Throwable, Single>) would be the thing I need. I'll close this and wait for the PR ;) Thanks a lot!

[twz123]

See #3766 for second part...