Router render fn now shows transition with a

spinner

src/main/scala/nova/monadic_sfx/ui/components/router/FXRouter.scala

@@ -12,14 +12,17 @@ import nova.monadic_sfx.util.reactive.store.Middlewares
 import nova.monadic_sfx.util.reactive.store.Reducer
 import nova.monadic_sfx.util.reactive.store.Store
 import scalafx.scene.Parent
+import monix.reactive.Observable
+import nova.monadic_sfx.util.controls.JFXSpinner
+import scala.concurrent.duration._
+import monix.eval.Coeval
 
 object FXRouter {
 
   final case class State[P](page: P)
 
-  // @JsonCodec
   sealed abstract class Action[+T]
-  final case class Replace[T](p: T) extends Action[T]
+  final case class Replace[T](page: T) extends Action[T]
 
   object Action {
     implicit def codec[T: Encoder: Decoder]: Codec[Action[T]] = deriveCodec
@@ -29,8 +32,7 @@ object FXRouter {
 
 }
 
-class FXRouter[P](
-)(implicit E: Encoder[P], D: Decoder[P]) {
+class FXRouter[P]()(implicit E: Encoder[P], D: Decoder[P]) {
   import FXRouter._
 
   def store(initialPage: P, logger: Logger[Task]): Task[FXStore[P]] =
@@ -60,9 +62,26 @@ class FXRouter[P](
     }
 
   def render(
-      resolver: P => Task[Parent]
+      resolver: P => Task[Parent],
+      transitionDelay: FiniteDuration = 500.millis
   )(implicit store: FXStore[P]) =
-    store.mapEval { case (_, FXRouter.State(p)) => IOUtils.toTask(resolver(p)) }
+    store
+      .flatMap {
+        case (_, FXRouter.State(p)) =>
+          Observable.from(Coeval(new JFXSpinner)) ++ Observable.from(
+            IOUtils.toTask(
+              Task
+                .racePair(
+                  Task.sleep(transitionDelay),
+                  resolver(p)
+                )
+                .flatMap {
+                  case Left(_ -> fib)    => fib.join
+                  case Right(fib -> res) => fib.join >> Task.pure(res)
+                }
+            )
+          )
+      }
 
   def link(
       page: P,