format button only when there is a JSON element.

src/main/scala/Main.scala

@@ -35,6 +35,8 @@ object Main extends IOWebApp {
   def actions(store: Store): Resource[IO, HtmlDivElement[IO]] =
     div(
       cls := "flex flex-col space-y-1 my-3",
+      store.result.map {
+        case Right(_: Event) =>
           button(
             Styles.button,
             "format",
@@ -45,7 +47,9 @@ object Main extends IOWebApp {
                   .getOrElse(original)
               )
             ))
-      ),
+          )
+        case _ => div("")
+      },
       button(
         Styles.button,
         "generate event",