Add tapWithF to Kleisli

typelevel · May 13, 2018 · 045c101 · 045c101
1 parent 680a517
commit 045c101
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diff --git a/core/src/main/scala/cats/data/Kleisli.scala b/core/src/main/scala/cats/data/Kleisli.scala
@@ -75,6 +75,9 @@ final case class Kleisli[F[_], A, B](run: A => F[B]) { self =>
   def tapWith[C](f: (A, B) => C)(implicit F: Functor[F]): Kleisli[F, A, C] =
     Kleisli(a => F.map(run(a))(b => f(a, b)))
 
+  def tapWithF[C](f: (A, B) => F[C])(implicit F: FlatMap[F]): Kleisli[F, A, C] =
+    Kleisli(a => F.flatMap(run(a))(b => f(a, b)))
+
   def toReader: Reader[A, F[B]] = Kleisli[Id, A, F[B]](run)
 
   def apply(a: A): F[B] = run(a)

diff --git a/tests/src/test/scala/cats/tests/KleisliSuite.scala b/tests/src/test/scala/cats/tests/KleisliSuite.scala
@@ -228,6 +228,12 @@ class KleisliSuite extends CatsSuite {
     }
   }
 
+  test("tapWithF") {
+    forAll { (f: Kleisli[List, Int, String], g: (Int, String) => List[Boolean], i: Int) =>
+      f.run(i).flatMap(s => g(i, s)) should === (f.tapWithF(g).run(i))
+    }
+  }
+
   test("apply") {
     forAll { (f: Kleisli[List, Int, Int], i: Int) =>
       f.run(i) should === (f(i))