added to (#2780)

typelevel · Apr 9, 2019 · d3b6ee7 · d3b6ee7
1 parent ca425bf
commit d3b6ee7
Show file tree

Hide file tree

Showing 2 changed files with 8 additions and 0 deletions.
diff --git a/core/src/main/scala/cats/data/EitherT.scala b/core/src/main/scala/cats/data/EitherT.scala
@@ -15,6 +15,8 @@ import cats.syntax.either._
 final case class EitherT[F[_], A, B](value: F[Either[A, B]]) {
   def fold[C](fa: A => C, fb: B => C)(implicit F: Functor[F]): F[C] = F.map(value)(_.fold(fa, fb))
 
+  def foldF[C](fa: A => F[C], fb: B => F[C])(implicit F: FlatMap[F]): F[C] = F.flatMap(value)(_.fold(fa, fb))
+
   def isLeft(implicit F: Functor[F]): F[Boolean] = F.map(value)(_.isLeft)
 
   def isRight(implicit F: Functor[F]): F[Boolean] = F.map(value)(_.isRight)

diff --git a/tests/src/test/scala/cats/tests/EitherTSuite.scala b/tests/src/test/scala/cats/tests/EitherTSuite.scala
@@ -325,6 +325,12 @@ class EitherTSuite extends CatsSuite {
     }
   }
 
+  test("foldF with Id consistent with Either fold") {
+    forAll { (eithert: EitherT[Id, String, Int], f: String => Long, g: Int => Long) =>
+      eithert.foldF(f, g) should ===(eithert.value.fold(f, g))
+    }
+  }
+
   test("valueOr with Id consistent with Either valueOr") {
     forAll { (eithert: EitherT[Id, String, Int], f: String => Int) =>
       eithert.valueOr(f) should ===(eithert.value.valueOr(f))