utils.ScalaExtensions.scala Maven / Gradle / Ivy

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package utils

import scala.collection.BuildFrom

object ScalaExtensions {
  implicit class TraversableOnceOptionExtension[A, M[X] <: IterableOnce[X]](val in: M[Option[A]]) extends AnyVal {
    def sequence(implicit bf: BuildFrom[M[Option[A]], A, M[A]]): Option[M[A]] = {
      val init = Option(bf(in))
      in.iterator
        .foldLeft(init) { (acc, cur) =>
          acc.flatMap { results =>
            cur.map(result => results += result)
          }
        }
        .map(_.result())
    }
  }
}