diff --git a/docs/demos/counter/hooks/model.ts b/docs/demos/counter/hooks/model.ts
index 28ea015..b36f7b8 100644
--- a/docs/demos/counter/hooks/model.ts
+++ b/docs/demos/counter/hooks/model.ts
@@ -26,4 +26,3 @@ export const counter = createModel<RootModel, 'counter'>()({
     },
   }),
 })
-
diff --git a/src/core/Model.tsx b/src/core/Model.tsx
index 9bff22f..79ae568 100644
--- a/src/core/Model.tsx
+++ b/src/core/Model.tsx
@@ -145,7 +145,7 @@ export class Model<C extends ModelConfig> {
 
     if (typeof state === 'object') {
       newState = produce(state, draft => {
-        reducer(draft, ...payload)
+        return reducer(draft, ...payload)
       })
     } else {
       newState = reducer(state, ...payload)