Improve LiveView's API with inspiration from TEA

core/src/TestLiveView.scala

@@ -2,28 +2,23 @@ package scalive
 package playground
 
 import scalive.*
+import zio.*
 
-final case class MyModel(
+import TestView.*
-  cls: String = "text-xs",
+class TestView extends LiveView[Msg, Model]:
-  bool: Boolean = true,
-  elems: List[Elem] = List.empty)
-final case class Elem(name: String, age: Int)
 
-class TestView(initialModel: MyModel) extends LiveView[TestView.Event]:
+  def init = ZIO.succeed(Model())
-  import TestView.Event.*
 
-  private val modelVar = Var[MyModel](initialModel)
+  def update(model: Model) =
+    case Msg.UpdateModel(f) => ZIO.succeed(f(model))
 
-  def handleEvent =
+  def view(model: Dyn[Model]) =
-    case UpdateModel(f) => modelVar.update(f)
-
-  val el: HtmlElement =
     div(
       idAttr   := "42",
-      cls      := modelVar(_.cls),
+      cls      := model(_.cls),
-      disabled := modelVar(_.bool),
+      disabled := model(_.bool),
       ul(
-        modelVar(_.elems).splitByIndex((_, elem) =>
+        model(_.elems).splitByIndex((_, elem) =>
           li(
             "Nom: ",
             elem(_.name),
@@ -35,5 +30,12 @@ class TestView(initialModel: MyModel) extends LiveView[TestView.Event]:
     )
 
 object TestView:
-  enum Event:
+
-    case UpdateModel(f: MyModel => MyModel)
+  enum Msg:
+    case UpdateModel(f: Model => Model)
+
+  final case class Model(
+    cls: String = "text-xs",
+    bool: Boolean = true,
+    elems: List[Elem] = List.empty)
+  final case class Elem(name: String, age: Int)

core/src/main.scala

@@ -4,33 +4,31 @@ package playground
 import scalive.*
 import zio.json.*
 
-extension (lv: LiveView[?])
+extension (el: HtmlElement) def html: String = HtmlBuilder.build(el)
-  def renderHtml: String =
-    HtmlBuilder.build(lv.el)
 
+import TestView.*
 @main
 def main =
-  val initModel = MyModel(elems =
+  val initModel = Model(elems =
     List(
       Elem("a", 10),
       Elem("b", 15),
       Elem("c", 30)
     )
   )
-  val lv = TestView(initModel)
+  val modelVar = Var(initModel)
+  val lv       = TestView()
+  val el       = lv.view(modelVar)
   println("Init")
-  println(lv.renderHtml)
+  println(el.html)
-  println(lv.diff().toJsonPretty)
+  println(el.diff().toJsonPretty)
 
   println("Edit class attribue")
-  lv.handleEvent(
+  modelVar.update(_.copy(cls = "text-lg"))
-    TestView.Event.UpdateModel(_.copy(cls = "text-lg"))
+  println(el.diff().toJsonPretty)
-  )
-  println(lv.diff().toJsonPretty)
 
   println("Edit first and last")
-  lv.handleEvent(
+  modelVar.update(
-    TestView.Event.UpdateModel(
     _.copy(elems =
       List(
         Elem("x", 10),
@@ -39,13 +37,11 @@ def main =
       )
     )
   )
-  )
+  println(el.diff().toJsonPretty)
-  println(lv.diff().toJsonPretty)
+  println(el.diff().toJsonPretty)
-  println(lv.diff().toJsonPretty)
 
   println("Add one")
-  lv.handleEvent(
+  modelVar.update(
-    TestView.Event.UpdateModel(
     _.copy(elems =
       List(
         Elem("x", 10),
@@ -55,13 +51,11 @@ def main =
       )
     )
   )
-  )
+  println(el.diff().toJsonPretty)
-  println(lv.diff().toJsonPretty)
+  println(el.html)
-  println(lv.renderHtml)
 
   println("Remove first")
-  lv.handleEvent(
+  modelVar.update(
-    TestView.Event.UpdateModel(
     _.copy(elems =
       List(
         Elem("b", 15),
@@ -70,21 +64,18 @@ def main =
       )
     )
   )
-  )
+  println(el.diff().toJsonPretty)
-  println(lv.diff().toJsonPretty)
+  println(el.html)
-  println(lv.renderHtml)
 
   println("Remove all")
-  lv.handleEvent(
+  modelVar.update(
-    TestView.Event.UpdateModel(
     _.copy(
       cls = "text-lg",
       bool = false,
       elems = List.empty
     )
   )
-  )
+  println(el.diff().toJsonPretty)
-  println(lv.diff().toJsonPretty)
+  println(el.diff().toJsonPretty)
-  println(lv.diff().toJsonPretty)
+  println(el.html)
-  println(lv.renderHtml)
 end main

core/src/scalive/Diff.scala

@@ -46,5 +46,5 @@ object Diff:
       case Diff.Value(value)         => Json.Str(value)
       case Diff.Dynamic(index, diff) =>
         Json.Obj(index.toString -> toJson(diff))
-      case Diff.Deleted => Json.Bool(false)
+      case Diff.Deleted => Json.Str("")
 end Diff

core/src/scalive/Dyn.scala

@@ -46,7 +46,7 @@ extension [T](parent: Dyn[List[T]])
       )
     )
 
-class Var[T] private (initial: T) extends Dyn[T]:
+private class Var[T] private (initial: T) extends Dyn[T]:
   private[scalive] var currentValue: T  = initial
   private[scalive] var changed: Boolean = true
   def set(value: T): Unit               =
@@ -61,10 +61,10 @@ class Var[T] private (initial: T) extends Dyn[T]:
   private[scalive] def setUnchanged(): Unit                 = changed = false
   private[scalive] inline def sync(): Unit                  = ()
   private[scalive] def callOnEveryChild(f: T => Unit): Unit = f(currentValue)
-object Var:
+private object Var:
   def apply[T](initial: T): Var[T] = new Var(initial)
 
-class DerivedVar[I, O] private[scalive] (parent: Var[I], f: I => O) extends Dyn[O]:
+private class DerivedVar[I, O] private[scalive] (parent: Var[I], f: I => O) extends Dyn[O]:
   private[scalive] var currentValue: O  = f(parent.currentValue)
   private[scalive] var changed: Boolean = true
 
@@ -88,7 +88,7 @@ class DerivedVar[I, O] private[scalive] (parent: Var[I], f: I => O) extends Dyn[
 
   private[scalive] def callOnEveryChild(f: O => Unit): Unit = f(currentValue)
 
-class SplitVar[I, O, Key](
+private class SplitVar[I, O, Key](
   parent: Dyn[List[I]],
   key: I => Key,
   project: (Key, Dyn[I]) => O):

core/src/scalive/HtmlElement.scala

@@ -22,12 +22,18 @@ class HtmlElement(val tag: HtmlTag, val mods: Vector[Mod]):
     mods.collect { case mod: (Mod.Attr & DynamicMod) => mod }
   def dynamicContentMods: Seq[Mod.Content & DynamicMod] =
     mods.collect { case mod: (Mod.Content & DynamicMod) => mod }
-  private[scalive] def syncAll(): Unit         = mods.foreach(_.syncAll())
-  private[scalive] def setAllUnchanged(): Unit = dynamicMods.foreach(_.setAllUnchanged())
 
   def prepended(mod: Mod*): HtmlElement = HtmlElement(tag, mods.prependedAll(mod))
   def apended(mod: Mod*): HtmlElement   = HtmlElement(tag, mods.appendedAll(mod))
 
+  private[scalive] def syncAll(): Unit         = mods.foreach(_.syncAll())
+  private[scalive] def setAllUnchanged(): Unit = dynamicMods.foreach(_.setAllUnchanged())
+  private[scalive] def diff(trackUpdates: Boolean = true): Diff =
+    syncAll()
+    val diff = DiffBuilder.build(this, trackUpdates = trackUpdates)
+    setAllUnchanged()
+    diff
+
 class HtmlTag(val name: String, val void: Boolean = false):
   def apply(mods: Mod*): HtmlElement = HtmlElement(this, mods.toVector)
 

core/src/scalive/LiveView.scala

@@ -1,11 +1,9 @@
 package scalive
 
-trait LiveView[Event]:
+import zio.*
-  def handleEvent: Event => Unit
-  val el: HtmlElement
 
-  private[scalive] def diff(trackUpdates: Boolean = true): Diff =
+trait LiveView[Msg, Model]:
-    el.syncAll()
+  def init: Task[Model]
-    val diff = DiffBuilder.build(el, trackUpdates = trackUpdates)
+  def update(model: Model): Msg => Task[Model]
-    el.setAllUnchanged()
+  def view(model: Dyn[Model]): HtmlElement
-    diff
+  // def subscriptions(model: Model): ZStream[Any, Nothing, Msg]

core/test/src/scalive/LiveViewSpec.scala

@@ -14,7 +14,6 @@ object LiveViewSpec extends TestSuite:
     cls: String = "text-sm",
     items: List[NestedModel] = List.empty)
   final case class NestedModel(name: String, age: Int)
-  final case class UpdateEvent(f: TestModel => TestModel)
 
   def assertEqualsDiff(el: HtmlElement, expected: Json, trackChanges: Boolean = true) =
     el.syncAll()
@@ -26,15 +25,12 @@ object LiveViewSpec extends TestSuite:
   val tests = Tests {
 
     test("Static only") {
-      val lv =
-        new LiveView[Nothing]:
       val el = div("Static string")
-          def handleEvent = _ => ()
+      el.syncAll()
-      lv.el.syncAll()
 
       test("init") {
         assertEqualsDiff(
-          lv.el,
+          el,
           Json.Obj(
             "s" -> Json.Arr(Json.Str("<div>Static string</div>"))
           ),
@@ -42,27 +38,24 @@ object LiveViewSpec extends TestSuite:
         )
       }
       test("diff") {
-        assertEqualsDiff(lv.el, emptyDiff)
+        assertEqualsDiff(el, emptyDiff)
       }
     }
 
     test("Dynamic string") {
-      val lv =
-        new LiveView[UpdateEvent]:
       val model = Var(TestModel())
       val el    =
         div(
           h1(model(_.title)),
           p(model(_.otherString))
         )
-          def handleEvent = evt => model.update(evt.f)
 
-      lv.el.syncAll()
+      el.syncAll()
-      lv.el.setAllUnchanged()
+      el.setAllUnchanged()
 
       test("init") {
         assertEqualsDiff(
-          lv.el,
+          el,
           Json
             .Obj(
               "s" -> Json.Arr(Json.Str("<div><h1>"), Json.Str("</h1><p>"), Json.Str("</p></div>")),
@@ -73,24 +66,24 @@ object LiveViewSpec extends TestSuite:
         )
       }
       test("diff no update") {
-        assertEqualsDiff(lv.el, emptyDiff)
+        assertEqualsDiff(el, emptyDiff)
       }
       test("diff with update") {
-        lv.handleEvent(UpdateEvent(_.copy(title = "title updated")))
+        model.update(_.copy(title = "title updated"))
         assertEqualsDiff(
-          lv.el,
+          el,
           Json.Obj("0" -> Json.Str("title updated"))
         )
       }
       test("diff with update and no change") {
-        lv.handleEvent(UpdateEvent(_.copy(title = "title value")))
+        model.update(_.copy(title = "title value"))
-        assertEqualsDiff(lv.el, emptyDiff)
+        assertEqualsDiff(el, emptyDiff)
       }
       test("diff with update in multiple commands") {
-        lv.handleEvent(UpdateEvent(_.copy(title = "title updated")))
+        model.update(_.copy(title = "title updated"))
-        lv.handleEvent(UpdateEvent(_.copy(otherString = "other string updated")))
+        model.update(_.copy(otherString = "other string updated"))
         assertEqualsDiff(
-          lv.el,
+          el,
           Json
             .Obj(
               "0" -> Json.Str("title updated"),
@@ -101,19 +94,16 @@ object LiveViewSpec extends TestSuite:
     }
 
     test("Dynamic attribute") {
-      val lv =
-        new LiveView[UpdateEvent]:
       val model = Var(TestModel())
       val el    =
         div(cls := model(_.cls))
-          def handleEvent = evt => model.update(evt.f)
 
-      lv.el.syncAll()
+      el.syncAll()
-      lv.el.setAllUnchanged()
+      el.setAllUnchanged()
 
       test("init") {
         assertEqualsDiff(
-          lv.el,
+          el,
           Json
             .Obj(
               "s" -> Json
@@ -124,20 +114,18 @@ object LiveViewSpec extends TestSuite:
         )
       }
       test("diff no update") {
-        assertEqualsDiff(lv.el, emptyDiff)
+        assertEqualsDiff(el, emptyDiff)
       }
       test("diff with update") {
-        lv.handleEvent(UpdateEvent(_.copy(cls = "text-md")))
+        model.update(_.copy(cls = "text-md"))
         assertEqualsDiff(
-          lv.el,
+          el,
           Json.Obj("0" -> Json.Str("text-md"))
         )
       }
     }
 
     test("when mod") {
-      val lv =
-        new LiveView[UpdateEvent]:
       val model = Var(TestModel())
       val el    =
         div(
@@ -145,14 +133,13 @@ object LiveViewSpec extends TestSuite:
             div("static string", model(_.nestedTitle))
           )
         )
-          def handleEvent = evt => model.update(evt.f)
 
-      lv.el.syncAll()
+      el.syncAll()
-      lv.el.setAllUnchanged()
+      el.setAllUnchanged()
 
       test("init") {
         assertEqualsDiff(
-          lv.el,
+          el,
           Json
             .Obj(
               "s" -> Json.Arr(Json.Str("<div>"), Json.Str("</div>")),
@@ -162,16 +149,16 @@ object LiveViewSpec extends TestSuite:
         )
       }
       test("diff no update") {
-        assertEqualsDiff(lv.el, emptyDiff)
+        assertEqualsDiff(el, emptyDiff)
       }
       test("diff with unrelated update") {
-        lv.handleEvent(UpdateEvent(_.copy(title = "title updated")))
+        model.update(_.copy(title = "title updated"))
-        assertEqualsDiff(lv.el, emptyDiff)
+        assertEqualsDiff(el, emptyDiff)
       }
       test("diff when true and nested update") {
-        lv.handleEvent(UpdateEvent(_.copy(bool = true)))
+        model.update(_.copy(bool = true))
         assertEqualsDiff(
-          lv.el,
+          el,
           Json.Obj(
             "0" ->
               Json
@@ -184,12 +171,12 @@ object LiveViewSpec extends TestSuite:
         )
       }
       test("diff when nested change") {
-        lv.handleEvent(UpdateEvent(_.copy(bool = true)))
+        model.update(_.copy(bool = true))
-        lv.el.syncAll()
+        el.syncAll()
-        lv.el.setAllUnchanged()
+        el.setAllUnchanged()
-        lv.handleEvent(UpdateEvent(_.copy(bool = true, nestedTitle = "nested title updated")))
+        model.update(_.copy(bool = true, nestedTitle = "nested title updated"))
         assertEqualsDiff(
-          lv.el,
+          el,
           Json.Obj(
             "0" ->
               Json
@@ -209,8 +196,6 @@ object LiveViewSpec extends TestSuite:
           NestedModel("c", 20)
         )
       )
-      val lv =
-        new LiveView[UpdateEvent]:
       val model = Var(initModel)
       val el    =
         div(
@@ -225,14 +210,13 @@ object LiveViewSpec extends TestSuite:
             )
           )
         )
-          def handleEvent = evt => model.update(evt.f)
 
-      lv.el.syncAll()
+      el.syncAll()
-      lv.el.setAllUnchanged()
+      el.setAllUnchanged()
 
       test("init") {
         assertEqualsDiff(
-          lv.el,
+          el,
           Json
             .Obj(
               "s" -> Json.Arr(Json.Str("<div><ul>"), Json.Str("</ul></div>")),
@@ -263,18 +247,16 @@ object LiveViewSpec extends TestSuite:
         )
       }
       test("diff no update") {
-        assertEqualsDiff(lv.el, emptyDiff)
+        assertEqualsDiff(el, emptyDiff)
       }
       test("diff with unrelated update") {
-        lv.handleEvent(UpdateEvent(_.copy(title = "title updated")))
+        model.update(_.copy(title = "title updated"))
-        assertEqualsDiff(lv.el, emptyDiff)
+        assertEqualsDiff(el, emptyDiff)
       }
       test("diff with item changed") {
-        lv.handleEvent(
+        model.update(_.copy(items = initModel.items.updated(2, NestedModel("c", 99))))
-          UpdateEvent(_.copy(items = initModel.items.updated(2, NestedModel("c", 99))))
-        )
         assertEqualsDiff(
-          lv.el,
+          el,
           Json.Obj(
             "0" ->
               Json
@@ -290,13 +272,9 @@ object LiveViewSpec extends TestSuite:
         )
       }
       test("diff with item added") {
-        lv.handleEvent(
+        model.update(_.copy(items = initModel.items.appended(NestedModel("d", 35))))
-          UpdateEvent(
-            _.copy(items = initModel.items.appended(NestedModel("d", 35)))
-          )
-        )
         assertEqualsDiff(
-          lv.el,
+          el,
           Json.Obj(
             "0" ->
               Json
@@ -313,13 +291,9 @@ object LiveViewSpec extends TestSuite:
         )
       }
       test("diff with first item removed") {
-        lv.handleEvent(
+        model.update(_.copy(items = initModel.items.tail))
-          UpdateEvent(
-            _.copy(items = initModel.items.tail)
-          )
-        )
         assertEqualsDiff(
-          lv.el,
+          el,
           Json.Obj(
             "0" ->
               Json
@@ -340,9 +314,9 @@ object LiveViewSpec extends TestSuite:
         )
       }
       test("diff all removed") {
-        lv.handleEvent(UpdateEvent(_.copy(items = List.empty)))
+        model.update(_.copy(items = List.empty))
         assertEqualsDiff(
-          lv.el,
+          el,
           Json.Obj(
             "0" ->
               Json

example/src/ExampleLiveView.scala

@@ -1,16 +1,16 @@
-import ExampleLiveView.Event
 import monocle.syntax.all.*
 import scalive.*
+import zio.*
 import zio.json.*
 
-final case class ExampleModel(elems: List[NestedModel], cls: String = "text-xs")
+import ExampleLiveView.*
-final case class NestedModel(name: String, age: Int)
+class ExampleLiveView(someParam: String) extends LiveView[Msg, Model]:
 
-class ExampleLiveView(someParam: String) extends LiveView[Event]:
+  def init = ZIO.succeed(
-
+    Model(
-  val model = Var(
+      isVisible = true,
-    ExampleModel(
+      counter = 0,
-      List(
+      elems = List(
         NestedModel("a", 10),
         NestedModel("b", 15),
         NestedModel("c", 20)
@@ -18,11 +18,17 @@ class ExampleLiveView(someParam: String) extends LiveView[Event]:
     )
   )
 
-  def handleEvent =
+  def update(model: Model) =
-    case Event.Event(value) =>
+    case Msg.IncAge(value) =>
-      model.update(_.focus(_.elems.index(2).age).modify(_ + value))
+      ZIO.succeed(model.focus(_.elems.index(2).age).modify(_ + value))
+    case Msg.ToggleCounter =>
+      ZIO.succeed(model.focus(_.isVisible).modify(!_))
+    case Msg.IncCounter =>
+      ZIO.succeed(model.focus(_.counter).modify(_ + 1))
+    case Msg.DecCounter =>
+      ZIO.succeed(model.focus(_.counter).modify(_ - 1))
 
-  val el =
+  def view(model: Dyn[Model]) =
     div(
       h1(someParam),
       h2(model(_.cls)),
@@ -39,12 +45,39 @@ class ExampleLiveView(someParam: String) extends LiveView[Event]:
         )
       ),
       button(
-        phx.click := Event.Event(1),
+        phx.click := Msg.IncAge(1),
         "Inc age"
+      ),
+      br(),
+      br(),
+      br(),
+      button(
+        phx.click := Msg.ToggleCounter,
+        model(_.isVisible match
+          case true  => "Hide counter"
+          case false => "Show counter")
+      ),
+      model.when(_.isVisible)(
+        div(
+          button(phx.click := Msg.DecCounter, "-"),
+          div(model(_.counter.toString)),
+          button(phx.click := Msg.IncCounter, "+")
+        )
       )
     )
 end ExampleLiveView
 
 object ExampleLiveView:
-  enum Event derives JsonCodec:
+
-    case Event(value: Int)
+  enum Msg derives JsonCodec:
+    case IncAge(value: Int)
+    case ToggleCounter
+    case IncCounter
+    case DecCounter
+
+  final case class Model(
+    isVisible: Boolean,
+    counter: Int,
+    elems: List[NestedModel],
+    cls: String = "text-xs")
+  final case class NestedModel(name: String, age: Int)

zio/src/scalive/LiveRouter.scala

@@ -15,19 +15,22 @@ import zio.stream.ZStream
 import java.util.Base64
 import scala.util.Random
 
-final case class LiveRoute[A, Event: JsonCodec](
+final case class LiveRoute[A, Msg: JsonCodec, Model](
   path: PathCodec[A],
-  liveviewBuilder: (A, Request) => LiveView[Event]):
+  liveviewBuilder: (A, Request) => LiveView[Msg, Model]):
-  val eventCodec = JsonCodec[Event]
+  val messageCodec = JsonCodec[Msg]
 
-  def toZioRoute(rootLayout: HtmlElement => HtmlElement): Route[Any, Nothing] =
+  def toZioRoute(rootLayout: HtmlElement => HtmlElement): Route[Any, Throwable] =
     Method.GET / path -> handler { (params: A, req: Request) =>
       val lv         = liveviewBuilder(params, req)
       val id: String =
         s"phx-${Base64.getUrlEncoder().withoutPadding().encodeToString(Random().nextBytes(12))}"
       val token = Token.sign("secret", id, "")
-      lv.el.syncAll()
+      for
-      Response.html(
+        initModel <- lv.init
+        el = lv.view(Var(initModel))
+        _  = el.syncAll()
+      yield Response.html(
         Html.raw(
           HtmlBuilder.build(
             rootLayout(
@@ -35,15 +38,16 @@ final case class LiveRoute[A, Event: JsonCodec](
                 idAttr      := id,
                 phx.main    := true,
                 phx.session := token,
-                lv.el
+                el
               )
             )
           )
         )
       )
     }
+end LiveRoute
 
-class LiveChannel(private val sockets: SubscriptionRef[Map[String, Socket[?]]]):
+class LiveChannel(private val sockets: SubscriptionRef[Map[String, Socket[?, ?]]]):
   def diffsStream: ZStream[Any, Nothing, (LiveResponse, Meta)] =
     sockets.changes
       .map(m =>
@@ -51,12 +55,12 @@ class LiveChannel(private val sockets: SubscriptionRef[Map[String, Socket[?]]]):
           .mergeAllUnbounded()(m.values.map(_.outbox).toList*)
       ).flatMapParSwitch(1, 1)(identity)
 
-  def join[Event: JsonCodec](
+  def join[Msg: JsonCodec, Model](
     id: String,
     token: String,
-    lv: LiveView[Event],
+    lv: LiveView[Msg, Model],
     meta: WebSocketMessage.Meta
-  ): URIO[Scope, Unit] =
+  ): RIO[Scope, Unit] =
     sockets.updateZIO { m =>
       m.get(id) match
         case Some(socket) =>
@@ -78,7 +82,7 @@ class LiveChannel(private val sockets: SubscriptionRef[Map[String, Socket[?]]]):
           socket.inbox
             .offer(
               value
-                .fromJson(using socket.clientEventCodec.decoder)
+                .fromJson(using socket.messageCodec.decoder)
                 .getOrElse(throw new IllegalArgumentException())
                 -> meta
             ).unit
@@ -91,7 +95,7 @@ object LiveChannel:
   def make(): UIO[LiveChannel] =
     SubscriptionRef.make(Map.empty).map(new LiveChannel(_))
 
-class LiveRouter(rootLayout: HtmlElement => HtmlElement, liveRoutes: List[LiveRoute[?, ?]]):
+class LiveRouter(rootLayout: HtmlElement => HtmlElement, liveRoutes: List[LiveRoute[?, ?, ?]]):
 
   private val socketApp: WebSocketApp[Any] =
     Handler.webSocket { channel =>
@@ -155,7 +159,7 @@ class LiveRouter(rootLayout: HtmlElement => HtmlElement, liveRoutes: List[LiveRo
                 val pathParams = route.path.decode(req.path).getOrElse(???)
                 val lv         = route.liveviewBuilder(pathParams, req)
                 liveChannel
-                  .join(message.topic, session, lv, message.meta)(using route.eventCodec)
+                  .join(message.topic, session, lv, message.meta)(using route.messageCodec)
                   .map(_ => None)
 
               }.getOrElse(ZIO.succeed(None))
@@ -168,12 +172,15 @@ class LiveRouter(rootLayout: HtmlElement => HtmlElement, liveRoutes: List[LiveRo
     end match
   end handleMessage
 
-  val routes: Routes[Any, Response] =
+  val routes: Routes[Any, Nothing] =
-    Routes.fromIterable(
+    Routes
+      .fromIterable(
         liveRoutes
           .map(route => route.toZioRoute(rootLayout))
           .prepended(
             Method.GET / "live" / "websocket" -> handler(socketApp.toResponse)
           )
+      ).handleErrorZIO(e =>
+        ZIO.logErrorCause(Cause.die(e)).as(Response(status = Status.InternalServerError))
       )
 end LiveRouter

zio/src/scalive/Socket.scala

@@ -6,34 +6,38 @@ import zio.Queue
 import zio.json.*
 import zio.stream.ZStream
 
-final case class Socket[Event: JsonCodec] private (
+final case class Socket[Msg: JsonCodec, Model] private (
   id: String,
   token: String,
-  inbox: Queue[(Event, WebSocketMessage.Meta)],
+  inbox: Queue[(Msg, WebSocketMessage.Meta)],
   outbox: ZStream[Any, Nothing, (LiveResponse, WebSocketMessage.Meta)],
-  fiber: Fiber.Runtime[Nothing, Unit],
+  fiber: Fiber.Runtime[Throwable, Unit],
   shutdown: UIO[Unit]):
-  val clientEventCodec = JsonCodec[Event]
+  val messageCodec = JsonCodec[Msg]
 
 object Socket:
-  def start[Event: JsonCodec](
+  def start[Msg: JsonCodec, Model](
     id: String,
     token: String,
-    lv: LiveView[Event],
+    lv: LiveView[Msg, Model],
     meta: WebSocketMessage.Meta
-  ): URIO[Scope, Socket[Event]] =
+  ): RIO[Scope, Socket[Msg, Model]] =
     for
-      inbox  <- Queue.bounded[(Event, WebSocketMessage.Meta)](4)
+      inbox     <- Queue.bounded[(Msg, WebSocketMessage.Meta)](4)
       outHub    <- Hub.bounded[(LiveResponse, WebSocketMessage.Meta)](4)
-      initDiff = lv.diff(trackUpdates = false)
+      initModel <- lv.init
-      lvRef <- Ref.make(lv)
+      modelVar = Var(initModel)
+      el       = lv.view(modelVar)
+      ref <- Ref.make((modelVar, el))
+      initDiff = el.diff(trackUpdates = false)
       fiber <- ZStream
                  .fromQueue(inbox)
                  .mapZIO { (msg, meta) =>
                    for
-                     lv <- lvRef.get
+                     (modelVar, el) <- ref.get
-                     _    = lv.handleEvent(msg)
+                     updatedModel   <- lv.update(modelVar.currentValue)(msg)
-                     diff = lv.diff()
+                     _    = modelVar.set(updatedModel)
+                     diff = el.diff()
                      _ <- outHub.publish(LiveResponse.Diff(diff) -> meta)
                    yield ()
                  }
@@ -42,4 +46,5 @@ object Socket:
       stop = inbox.shutdown *> outHub.shutdown *> fiber.interrupt.unit
       diffStream <- ZStream.fromHubScoped(outHub)
       outbox = ZStream.succeed(LiveResponse.InitDiff(initDiff) -> meta) ++ diffStream
-    yield Socket[Event](id, token, inbox, outbox, fiber, stop)
+    yield Socket[Msg, Model](id, token, inbox, outbox, fiber, stop)
+end Socket