arrow-core-data / arrow.core / kotlin.collections.Map / padZip
padZip
fun <K, A, B> Map<K, A>.padZip(other: Map<K, B>): Map<K, Pair<A?, B?>>
Align two structures as in zip, but filling in blanks with null.
fun <K, A, B, C> Map<K, A>.padZip(other: Map<K, B>, fa: (K, A?, B?) -> C): Map<K, C>