diff --git a/README.md b/README.md
index fd32473..3db2dcf 100644
--- a/README.md
+++ b/README.md
@@ -183,15 +183,20 @@ TypeScript Example
 // StateType and ActionsParamType definition
 // ...
 
-const Model = {
+const Model: ModelType<StateType, ActionsParamType> = {
   actions: {
     increment: async (s, _, params) => {
+      // issue: https://github.com/Microsoft/TypeScript/issues/29196
+      // async function return produce need define type manually.
       return (state: typeof s) => {
         state.counter += params || 1
       }
+    },
+    decrease: (s, _, params) => s => {
+      s.counter += params || 1
     }
   }
-} as ModelType<StateType, ActionsParamType>
+}
 ```
 
 JavaScript Example
diff --git a/example/model/home.model.ts b/example/model/home.model.ts
index e066567..edbf91c 100644
--- a/example/model/home.model.ts
+++ b/example/model/home.model.ts
@@ -14,10 +14,10 @@ type ActionsParamType = {
   get: undefined
 }
 
-const Model = {
+const Model: ModelType<StateType, ActionsParamType> = {
   actions: {
-    increment: async (s, __, params) => {
-      return (state: typeof s) => {
+    increment: async (_, __, params) => {
+      return (state: typeof _) => {
         state.counter += params || 1
       }
     },
@@ -50,7 +50,7 @@ const Model = {
     }
   },
   state: initialState
-} as ModelType<StateType, ActionsParamType>
+}
 
 export default Model
 
diff --git a/package.json b/package.json
index 454db1c..7eff934 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "react-modelx",
-  "version": "1.0.5",
+  "version": "1.0.6",
   "description": "The State management library for React",
   "main": "./dist/index",
   "module": "./dist/index",
@@ -16,7 +16,7 @@
   ],
   "author": "ArrayZoneYour <hustliyidong@gmail.com>",
   "license": "MIT",
-  "dependencies": {
+  "peerDependencies": {
     "immer": "^1.9.3",
     "react": "^16.7.0-alpha.2",
     "react-dom": "^16.7.0-alpha.2"
diff --git a/src/index.d.ts b/src/index.d.ts
index ebea893..7b8bb45 100644
--- a/src/index.d.ts
+++ b/src/index.d.ts
@@ -1,17 +1,16 @@
-type State<T> = T
-
-type Action<T, P = any, ActionKeys = []> = (
-  state: T,
-  actions: getConsumerActionsType<Actions<T, ActionKeys>>,
+// Very Sad, Promise<ProduceFunc<S>> can not work with Partial<S> | ProduceFunc<S>
+type Action<S = {}, P = any, ActionKeys = {}> = (
+  state: S,
+  actions: getConsumerActionsType<Actions<S, ActionKeys>>,
   params: P
-) => Partial<T> | ProduceFunc<T>
+) => Partial<S> | Promise<Partial<S>> | ProduceFunc<S> | Promise<ProduceFunc<S>>
 
-type ProduceFunc = <T>(state?: T) => {}
+type ProduceFunc<S> = (state?: S) => {}
 
 type ProviderProps = { [name: string]: ModelType }
 
-type Actions<T, ActionKeys> = {
-  [P in keyof ActionKeys]: Action<T, ActionKeys[P], ActionKeys>
+type Actions<S = {}, ActionKeys = {}> = {
+  [P in keyof ActionKeys]: Action<S, ActionKeys[P], ActionKeys>
 }
 
 interface Models {
@@ -29,10 +28,10 @@ type ArgumentTypes<F extends Function> = F extends (...args: infer A) => any
   ? A
   : never
 
-type getConsumerActionsType<T> = {
-  [P in keyof T]: ArgumentTypes<T[P]>[2] extends undefined
-    ? (params?: ArgumentTypes<T[P]>[2]) => ReturnType<T[P]>
-    : (params: ArgumentTypes<T[P]>[2]) => ReturnType<T[P]>
+type getConsumerActionsType<A extends Actions> = {
+  [P in keyof A]: ArgumentTypes<A[P]>[2] extends undefined
+    ? <K extends keyof A>(params?: ArgumentTypes<A[K]>[2]) => ReturnType<A[K]>
+    : <K extends keyof A>(params: ArgumentTypes<A[K]>[2]) => ReturnType<A[K]>
 }
 
-type Get<T, N extends keyof T> = T[N]
+type Get<Object, K extends keyof Object> = Object[K]