diff --git a/SortableCell.js b/SortableCell.js
index 4bec6bc..1f26d32 100644
--- a/SortableCell.js
+++ b/SortableCell.js
@@ -1,6 +1,6 @@
+import PropTypes from 'prop-types';
 import React, {
-    PropTypes,
-    Component,
+    Component
 } from 'react'
 import {
     View, Text,
diff --git a/SortableSudokuGrid.js b/SortableSudokuGrid.js
index ca722d1..1f8c5c1 100644
--- a/SortableSudokuGrid.js
+++ b/SortableSudokuGrid.js
@@ -4,10 +4,9 @@
  * Released under the MIT license
  * Copyright (c) 2016 react-native-component <moonsunfall@aliyun.com>
  */
-
+import PropTypes from 'prop-types';
 import React, {
-    PropTypes,
-    Component,
+    Component
 } from 'react'
 import {
     View,
@@ -138,7 +137,7 @@ class SortableSudokuGrid extends Component {
     componentWillReceiveProps (nextProps) {
         let { sortable, dataSource, } = nextProps
         let { sortable: lastSortable,  dataSource: lastDataSource, } = this.props
-        let newState
+        let newState = {}
         if (sortable !== lastSortable) {
             !newState && (newState = {})
             newState.sortable = sortable
diff --git a/package.json b/package.json
index 5af36ce..ccaea4b 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,7 @@
   },
   "homepage": "https://github.com/react-native-component/react-native-smart-sortable-sudoku-grid#readme",
   "dependencies": {
+    "prop-types": "^15.6.2",
     "react-native-smart-timer-enhance": "^1.0.2"
   }
 }