mapEither

fun <E : Throwable, A, B> IO<A>.mapEither(f: (A) -> EitherOf<E, B>): IO<B>

Transform the value of an IO into an Either and consequently flatten into an IO

Return

success when f results in Either.Right or error when f results in Either.Left

fun main(args: Array) { fun Int.increment() = Either.right(this + 1) val result = //sampleStart IO.just(1).mapEither { it.increment() } //sampleEnd println(result.unsafeRunSyncEither()) }