[GitHub] [incubator-pekko] He-Pin commented on a diff in pull request #591: =str Make use of statefulMap to implement zipWithIndex.

["He-Pin (via GitHub)" <gi...@apache.org>]

He-Pin commented on code in PR #591:
URL: https://github.com/apache/incubator-pekko/pull/591#discussion_r1307169385


##########
stream/src/main/scala/org/apache/pekko/stream/scaladsl/Flow.scala:
##########
@@ -2881,16 +2881,9 @@ trait FlowOps[+Out, +Mat] {
    *
    * '''Cancels when''' downstream cancels
    */
-  def zipWithIndex: Repr[(Out, Long)] = {
-    statefulMapConcat[(Out, Long)] { () =>
-      var index: Long = 0L
-      elem => {
-        val zipped = (elem, index)
-        index += 1
-        immutable.Iterable[(Out, Long)](zipped)
-      }
-    }
-  }
+  def zipWithIndex: Repr[(Out, Long)] = statefulMap(() => 0L)({
+      case (index, out) => (index + 1L, (out, index))
+    }, _ => None).withAttributes(DefaultAttributes.zipWithIndex)

Review Comment:
   Add the `name`



##########
stream/src/main/scala/org/apache/pekko/stream/scaladsl/Flow.scala:
##########
@@ -2881,16 +2881,9 @@ trait FlowOps[+Out, +Mat] {
    *
    * '''Cancels when''' downstream cancels
    */
-  def zipWithIndex: Repr[(Out, Long)] = {
-    statefulMapConcat[(Out, Long)] { () =>
-      var index: Long = 0L
-      elem => {
-        val zipped = (elem, index)
-        index += 1
-        immutable.Iterable[(Out, Long)](zipped)
-      }
-    }
-  }
+  def zipWithIndex: Repr[(Out, Long)] = statefulMap(() => 0L)({
+      case (index, out) => (index + 1L, (out, index))
+    }, _ => None).withAttributes(DefaultAttributes.zipWithIndex)

Review Comment:
   Added the `name`



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