batchedFutures.scala

import scala.concurrent.Future

object Futures {
  def batchedTraverse[A, B](as: List[A], batchSize: Int, timeout: Int)(f: A => Future[B]) =
    as.grouped(batchSize).foldLeft(Future.successful(List.empty[B])) {
      case (accumulatorFuture, batch) => accumulatorFuture flatMap { accumulator =>
        Future.traverse(batch)(f) map { accumulator ++ _ }
      }
    }
}