packages/effect-fc/src/Form.ts

@@ -334,9 +334,23 @@ export const useOptionalInput: {
     yield* Hooks.useFork(() => Effect.all([
         Stream.runForEach(
             Stream.drop(field.encodedValueRef, 1),
+
             upstreamEncodedValue => Effect.whenEffect(
-                Ref.set(internalValueRef, upstreamEncodedValue),
-                Effect.andThen(internalValueRef, internalValue => !Equal.equals(upstreamEncodedValue, internalValue)),
+                Option.match(upstreamEncodedValue, {
+                    onSome: v => Effect.andThen(
+                        Ref.set(enabledRef, true),
+                        Ref.set(internalValueRef, v),
+                    ),
+                    onNone: () => Effect.andThen(
+                        Ref.set(enabledRef, false),
+                        Ref.set(internalValueRef, options.defaultValue),
+                    ),
+                }),
+
+                Effect.andThen(
+                    Effect.all([enabledRef, internalValueRef]),
+                    ([enabled, internalValue]) => !Equal.equals(upstreamEncodedValue, enabled ? Option.some(internalValue) : Option.none()),
+                ),
             ),
         ),