filterOption

fun <T> Iterable<Option<T>>.filterOption(): List<T>

fun <K, A> Map<K, Option<A>>.filterOption(): Map<K, A>

fun <A> Sequence<Option<A>>.filterOption(): Sequence<A>

Filters out all elements that are None, and unwraps the remaining elements Some values.

import arrow.core.None
import arrow.core.Some
import arrow.core.filterOption
import io.kotest.matchers.shouldBe

fun test() {
generateSequence(0) { it + 1 }
  .map { if (it % 2 == 0) Some(it) else None }
  .filterOption()
  .take(5)
  .toList() shouldBe listOf(0, 2, 4, 6, 8)
}