Is there a more functional approach to this? I don...

# codereview

[Philipp Mayer]

Is there a more functional approach to this?
I don't really like creating a new variable just to check if it is empty.
Thanks guys!

val newSmth = listOfObjects.filter { ... }
        if (newSmth.isNotEmpty()) {
            otherWorkflow.process(newSmth)
        }

[Jonathan Mew]

If nothing better exists, I guess you keep your function cleaner/more readable with something like

fun <E> List<E>.applyIfNotEmpty(action: (List<E>) -> Unit) {
        if(size > 0) {
            action(this)
        }
    }

so you can

objs.filter { it == 'a' }
    .applyIfNotEmpty (otherWorkflow::process)

There might well be something nice OOTB though

[araqnid]

listOfObjects.filter { … }.let { if (it.isNotEmpty()) otherWorflow.process(it) } ?

[araqnid]

or even
listOfObjects.filter {…}.takeUnless { it.isEmpty() }?.let { otherWorkflow.process(it) }

[araqnid]

depending on how much obfuscation you want to add 😉

[Milan Hruban]

if you want to be able to read that code again, I suggest going with your original solution 🙂

[Philipp Mayer]

Yeah, I will keep it as it is. Anyway, thanks for your ideas!

[andyg]

@araqnid’s first reply looks best. On the other hand, what happens if you send an empty list to otherWorkflow.process() ? If that method iterates through a list, the nothing should happen when the list is empty, thus no need for the empty check. If the method crashes or does something weird when the parameter is an empty list, it is probably cleaner and safer to do the empty check within the method itself.