Idiomatic way to return if not null in Kotlin

Question

I am looking for an idiomatic way to return if not null a variable in Kotlin. For example, I would like something such as:

for (item in list) {
  getNullableValue(item).? let {
    return it
  }
}

But it's not possible to return inside a let block in Kotlin.

Is there a good way to do this without having to do this:

for (item in list) {
  val nullableValue = getNullableValue(item)
  if (nullableValue != null) {
    return nullableValue
  }
}

Answer 1

It is possible to return from let, as you can read in the documentation:

The return-expression returns from the nearest enclosing function, i.e. foo. (Note that such non-local returns are supported only for lambda expressions passed to inline functions.)

let() is an inline function and therefore you automatically return from the enclosing function whenever you do return within let, like in this example:

fun foo() {
    ints.forEach {
        if (it == 0) return  // nonlocal return from inside lambda directly to the caller of foo()
        print(it)
    }
 }

To modify the behavior, "labels" can be used:

fun foo() {
    ints.forEach lit@ {
        if (it == 0) return@lit
        print(it)
    }
}

Answer 2

Not sure if this would be called idiomatic, but you could do this:

val nullableValue = list.find { it != null }
if (nullableValue != null) {
    return nullableValue
}

Edit:

Based on s1m0nw1's answer, you can probably reduce it to this:

list.find { it != null }?.let {
    return it
}