diff --git a/src/createStore.ts b/src/createStore.ts
index 31c9d20..4bf428a 100644
--- a/src/createStore.ts
+++ b/src/createStore.ts
@@ -1,42 +1,52 @@
+import { clone } from './clone';
 import { createEmitter } from './createEmitter';
 import { isFunction } from './isFunction';
 import { isObject } from './isObject';
 import { omit } from './omit';
 import { Obj } from './types';
 
+type Store<T> = T & { subscribe(fn: (s: T) => void): () => never };
+
 const { emit, on } = createEmitter();
+const { defineProperty, getOwnPropertyDescriptor } = Object;
 
-const handler = () => ({
-  get(obj: Obj, key: string) {
-    if (key === '_isProxy') return true;
-    const d = Object.getOwnPropertyDescriptor(obj, key);
-    const nok = isObject(obj[key]) && !obj[key]._isProxy && d?.writable;
-    nok && (obj[key] = new Proxy(obj[key], handler()));
-    return obj[key];
-  },
-  set(obj: Obj, key: string, val: unknown) {
-    if (obj[key] !== val) (obj[key] = val), emit('update');
-    return true;
-  },
-  deleteProperty(obj: Obj, key: string) {
-    delete obj[key];
-    emit('update');
-    return true;
-  },
-});
-
-export function createStore<T = Obj>(init: T): T & { subscribe(fn: (s: T) => void): () => never } {
-  const fns = <Function[]>[];
-  const subscribe = (fn: Function) => {
-    if (!fns.includes(fn)) fns.push(fn);
-    return () => {
-      const idx = fns.findIndex((l) => l === fn);
-      idx !== -1 && fns.splice(idx, 1);
-    };
+function handler() {
+  return {
+    get(obj: Obj, key: string) {
+      if (key === '_isProxy') return true;
+      const d = getOwnPropertyDescriptor(obj, key);
+      const nok = isObject(obj[key]) && !obj[key]._isProxy && d?.writable;
+      nok && (obj[key] = new Proxy(obj[key], handler()));
+      return obj[key];
+    },
+    set(obj: Obj, key: string, val: unknown) {
+      if (obj[key] !== val) (obj[key] = val), emit('update');
+      return true;
+    },
+    deleteProperty(obj: Obj, key: string) {
+      delete obj[key];
+      emit('update');
+      return true;
+    },
   };
+}
+
+export function createStore<T extends object>(data: T): Store<T> {
+  const fns = <Function[]>[];
+  const init = clone(data);
+
+  defineProperty(init, 'subscribe', {
+    value(fn: Function) {
+      if (!fns.includes(fn)) fns.push(fn);
+      return () => {
+        const idx = fns.findIndex((l) => l === fn);
+        idx !== -1 && fns.splice(idx, 1);
+      };
+    },
+  });
 
   let nextTickId = 0;
-  const store = new Proxy(Object.assign(init as never, { subscribe }), handler());
+  const store = new Proxy(init, handler());
   on('update', () => {
     const data = omit('subscribe', store);
     if (nextTickId) cancelAnimationFrame(nextTickId);
@@ -44,20 +54,17 @@ export function createStore<T = Obj>(init: T): T & { subscribe(fn: (s: T) => voi
   });
 
   for (const prop in init) {
-    const d = Object.getOwnPropertyDescriptor(init, prop);
+    const d = getOwnPropertyDescriptor(init, prop);
     if (d?.get && d?.configurable) {
-      Object.defineProperty(init, prop, {
+      defineProperty(init, prop, {
         get: d.get.bind(store),
-        configurable: false,
       });
     } else if (isFunction(init[prop])) {
-      Object.defineProperty(init, prop, {
+      defineProperty(init, prop, {
         value: (init[prop] as any).bind(store),
-        configurable: false,
-        writable: false,
       });
     }
   }
 
-  return store as never;
+  return store as Store<T>;
 }