Misc: Make base onAddedExternalObserver method abstract

raquo · Jan 4, 2023 · 1de61b2 · 1de61b2
1 parent 2ba55e3
commit 1de61b2
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Showing 3 changed files with 5 additions and 3 deletions.
diff --git a/src/main/scala/com/raquo/airstream/core/BaseObservable.scala b/src/main/scala/com/raquo/airstream/core/BaseObservable.scala
@@ -151,7 +151,7 @@ trait BaseObservable[+Self[+_] <: Observable[_], +A] extends Source[A] with Name
 
   protected[this] def addExternalObserver(observer: Observer[A], owner: Owner): Subscription
 
-  protected[this] def onAddedExternalObserver(@unused observer: Observer[A]): Unit = ()
+  protected[this] def onAddedExternalObserver(@unused observer: Observer[A]): Unit
 
   /** Child observable should call this method on its parents when it is started.
     * This observable calls [[onStart]] if this action has given it its first observer (internal or external).

diff --git a/src/main/scala/com/raquo/airstream/core/EventStream.scala b/src/main/scala/com/raquo/airstream/core/EventStream.scala
@@ -9,7 +9,7 @@ import com.raquo.airstream.debug.{DebuggableEventStream, Debugger, DebuggerEvent
 import com.raquo.airstream.distinct.DistinctEventStream
 import com.raquo.airstream.eventbus.EventBus
 import com.raquo.airstream.misc.generated._
-import com.raquo.airstream.misc.{CollectEventStream, DropEventStream, FilterEventStream, FoldLeftSignal, MapEventStream, SignalFromEventStream}
+import com.raquo.airstream.misc.{CollectEventStream, FilterEventStream, FoldLeftSignal, MapEventStream, SignalFromEventStream}
 import com.raquo.airstream.split.{SplittableEventStream, SplittableOneEventStream}
 import com.raquo.airstream.timing.{FutureEventStream, _}
 
@@ -130,6 +130,9 @@ trait EventStream[+A] extends Observable[A] with BaseObservable[EventStream, A]
     new DebuggerEventStream[A](this, debugger)
   }
 
+  /** This is used in Signal-s. It's a no-op for Streams. */
+  override protected def onAddedExternalObserver(observer: Observer[A]): Unit = ()
+
   override def toObservable: EventStream[A] = this
 
 }

diff --git a/src/main/scala/com/raquo/airstream/core/Signal.scala b/src/main/scala/com/raquo/airstream/core/Signal.scala
@@ -134,7 +134,6 @@ trait Signal[+A] extends Observable[A] with BaseObservable[Signal, A] with Signa
 
   // @TODO[API] Use pattern match instead when isInstanceOf performance is fixed: https://github.com/scala-js/scala-js/issues/3815
   override protected def onAddedExternalObserver(observer: Observer[A]): Unit = {
-    super.onAddedExternalObserver(observer)
     observer.onTry(tryNow()) // send current value immediately
   }