Support CallbackOption[Unit] being passed directly to event handling vdom

Closes #957

Author: japgolly

callback/src/main/scala/japgolly/scalajs/react/util/EffectCallback.scala

@@ -4,8 +4,9 @@ import japgolly.scalajs.react.callback._
 import scala.scalajs.js
 
 abstract class EffectFallbacks1 extends EffectFallbacks2 {
-  implicit def callback     : Effect.Sync [CallbackTo   ] = EffectCallback.callback
-  implicit def asyncCallback: Effect.Async[AsyncCallback] = EffectCallback.asyncCallback
+  implicit def callback      : Effect.Sync    [CallbackTo    ] = EffectCallback.callback
+  implicit def callbackOption: Effect.Dispatch[CallbackOption] = EffectCallback.callbackOption
+  implicit def asyncCallback : Effect.Async   [AsyncCallback ] = EffectCallback.asyncCallback
 }
 
 object EffectCallback {
@@ -82,6 +83,29 @@ object EffectCallback {
 
   // ===================================================================================================================
 
+  object callbackOption extends Dispatch[CallbackOption] {
+
+    override def delay[A](a: => A): CallbackOption[A] =
+      CallbackOption.delay(a)
+
+    override def pure[A](a: A): CallbackOption[A] =
+      CallbackOption.pure(a)
+
+    override def map[A, B](fa: CallbackOption[A])(f: A => B): CallbackOption[B] =
+      fa map f
+
+    override def flatMap[A, B](fa: CallbackOption[A])(f: A => CallbackOption[B]): CallbackOption[B] =
+      fa flatMap f
+
+    override def dispatch[A](fa: CallbackOption[A]): Unit =
+      fa.asCallback.void
+
+    override def dispatchFn[A](fa: => CallbackOption[A]): js.Function0[Unit] =
+      () => {fa.underlyingRepr(); ()}
+  }
+
+  // ===================================================================================================================
+
   object asyncCallback extends Async[AsyncCallback] with Dispatch.WithDefaults[AsyncCallback] {
     @inline override def delay[A](a: => A) =
       AsyncCallback.delay(a)

coreGeneric/src/main/scala-2/japgolly/scalajs/react/vdom/Attr.scala

@@ -64,21 +64,21 @@ object Attr {
   }
 
   trait EventCallback0 {
-    implicit def sync[F[_]](implicit F: Dispatch[F]): EventCallback[F[Unit]] =
+    implicit def dispatch[F[_]](implicit F: Dispatch[F]): EventCallback[F[Unit]] =
       new EventCallback(fa => F.dispatchFn(fa))
 
-    implicit def reusableSync[F[_]](implicit F: Dispatch[F]): EventCallback[Reusable[F[Unit]]] =
+    implicit def reusableDispatch[F[_]](implicit F: Dispatch[F]): EventCallback[Reusable[F[Unit]]] =
       new EventCallback(fa => F.dispatchFn(fa))
   }
 
   object EventCallback extends EventCallback0 {
     import DefaultEffects.{Sync => D}
 
     implicit val defaultSync: EventCallback[D[Unit]] =
-      sync(D)
+      dispatch(D)
 
     implicit lazy val reusableDefaultSync: EventCallback[Reusable[D[Unit]]] =
-      reusableSync(D)
+      reusableDispatch(D)
   }
 
   type EventHandler[E[+x <: dom.Node] <: facade.SyntheticEvent[x]] =

coreGeneric/src/main/scala-3/japgolly/scalajs/react/vdom/Attr.scala

@@ -80,21 +80,21 @@ object Attr {
   }
 
   trait EventCallback0 {
-    implicit def sync[F[_]](implicit F: Dispatch[F]): EventCallback[F[Unit]] =
+    implicit def dispatch[F[_]](implicit F: Dispatch[F]): EventCallback[F[Unit]] =
       new EventCallback(fa => F.dispatchFn(fa))
 
-    implicit def reusableSync[F[_]](implicit F: Dispatch[F]): EventCallback[Reusable[F[Unit]]] =
+    implicit def reusableDispatch[F[_]](implicit F: Dispatch[F]): EventCallback[Reusable[F[Unit]]] =
       new EventCallback(fa => F.dispatchFn(fa))
   }
 
   object EventCallback extends EventCallback0 {
     import DefaultEffects.{Sync => D}
 
     implicit val defaultSync: EventCallback[D[Unit]] =
-      sync(D)
+      dispatch(D)
 
     implicit lazy val reusableDefaultSync: EventCallback[Reusable[D[Unit]]] =
-      reusableSync(D)
+      reusableDispatch(D)
   }
 
   type EventHandler[E[+x <: dom.Node] <: facade.SyntheticEvent[x]] =

doc/changelog/2.0.0.md

@@ -337,6 +337,7 @@ You can run the script in the Migration section at the bottom of the page to aut
   * `TriStateCheckbox`'s `onKeyDown` handler was calling `event.preventDefault()` on unhandled keys
   * Fix the Scala 3 version of `renderBackend` to support polymorphic backends
     *(e.g. `renderBackend[Backend[X]]` where `X` is a type already in scope)*
+  * Support `CallbackOption[Unit]` being passed directly to event handling vdom
 
 * `TriStateCheckbox` now accepts an optional `Reusable[TagMod]` in its `Props` that will be applied to the `<input>`
 

tests/src/test/scala/japgolly/scalajs/react/core/vdom/VdomTest.scala

@@ -153,5 +153,13 @@ object VdomTest extends TestSuite {
       }
     }
 
+    "callbackOption" - {
+      "value" - assertCompiles(^.onKeyDown --> CallbackOption.pass)
+      "fn" - {
+        def keys(e: ReactKeyboardEventFromHtml): CallbackOption[Unit] = ???
+        assertCompiles(^.onKeyDown ==> keys)
+      }
+    }
+
   }
 }