anyone have a good idiom for solving this problem?...

# announcements

[joshua.ewer]

anyone have a good idiom for solving this problem?

given two nullable lists, a: List<String>? and b:List<String>?

if any are not null, return a concat list

else return null

[gildor]

Also

(b.orEmpty() + a.orEmpty()).takeIf { it.isNotEmpty() }

But little bit less efficient if both lists are null because will be created a new collection