DataGrid - fix types in demos after changing JSDoc types sync

apps/demos/Demos/DataGrid/AdvancedMasterDetailView/React/OrderHistory.tsx

@@ -13,7 +13,7 @@ interface OrderHistoryProps {
 }
 
 const OrderHistory = ({ productId }: OrderHistoryProps) => {
-  const [orderHistoryStore, setOrderHistoryStore] = useState<CustomStore | null>(null);
+  const [orderHistoryStore, setOrderHistoryStore] = useState<CustomStore | undefined>(undefined);
 
   useEffect(() => {
     if (productId) {

apps/demos/Demos/DataGrid/AdvancedMasterDetailView/ReactJs/OrderHistory.js

@@ -11,7 +11,7 @@ import { createStore } from 'devextreme-aspnet-data-nojquery';
 
 const url = 'https://js.devexpress.com/Demos/NetCore/api/DataGridAdvancedMasterDetailView';
 const OrderHistory = ({ productId }) => {
-  const [orderHistoryStore, setOrderHistoryStore] = useState(null);
+  const [orderHistoryStore, setOrderHistoryStore] = useState(undefined);
   useEffect(() => {
     if (productId) {
       const newOrderHistoryStore = createStore({

apps/demos/Demos/DataGrid/AdvancedMasterDetailView/Vue/OrderHistory.vue

@@ -55,7 +55,7 @@ const props = defineProps<{
 
 const url = 'https://js.devexpress.com/Demos/NetCore/api/DataGridAdvancedMasterDetailView';
 
-const orderHistoryStore = computed(() => (props.productId === null ? null : {
+const orderHistoryStore = computed(() => (props.productId === null ? undefined : {
   store: createStore({
     key: 'OrderID',
     loadParams: { ProductID: props.productId },

apps/demos/Demos/DataGrid/SignalRService/React/App.tsx

@@ -9,7 +9,7 @@ import ChangeCell from './ChangeCell.tsx';
 
 const App = () => {
   const [connectionStarted, setConnectionStarted] = useState(false);
-  const [dataSource, setDataSource] = useState<CustomStore | null>(null);
+  const [dataSource, setDataSource] = useState<CustomStore | undefined>(undefined);
 
   useEffect(() => {
     const hubConnection = new HubConnectionBuilder()

apps/demos/Demos/DataGrid/SignalRService/ReactJs/App.js

@@ -7,7 +7,7 @@ import ChangeCell from './ChangeCell.js';
 
 const App = () => {
   const [connectionStarted, setConnectionStarted] = useState(false);
-  const [dataSource, setDataSource] = useState(null);
+  const [dataSource, setDataSource] = useState(undefined);
   useEffect(() => {
     const hubConnection = new HubConnectionBuilder()
       .withUrl('https://js.devexpress.com/Demos/NetCore/liveUpdateSignalRHub', {

apps/demos/Demos/DataGrid/SignalRService/Vue/App.vue

@@ -66,7 +66,7 @@ import PriceCell from './PriceCell.vue';
 import ChangeCell from './ChangeCell.vue';
 
 const connectionStarted = ref(false);
-const dataSource = ref<CustomStore | null>(null);
+const dataSource = ref<CustomStore | undefined>(undefined);
 
 onMounted(() => {
   const hubConnection = new HubConnectionBuilder()

apps/demos/Demos/DataGrid/WebAPIService/React/MasterDetailGrid.tsx

@@ -18,7 +18,7 @@ const getMasterDetailGridDataSource = (id: number) => ({
 });
 
 const MasterDetailGrid = (props: DataGridTypes.MasterDetailTemplateData) => {
-  const [dataSource, setDataSource] = useState<DataSourceOptions | null>(null);
+  const [dataSource, setDataSource] = useState<DataSourceOptions | undefined>(undefined);
 
   useEffect(() => {
     const masterDetailDataSource = getMasterDetailGridDataSource(props.data.key);

apps/demos/Demos/DataGrid/WebAPIService/ReactJs/MasterDetailGrid.js

@@ -13,7 +13,7 @@ const getMasterDetailGridDataSource = (id) => ({
   }),
 });
 const MasterDetailGrid = (props) => {
-  const [dataSource, setDataSource] = useState(null);
+  const [dataSource, setDataSource] = useState(undefined);
   useEffect(() => {
     const masterDetailDataSource = getMasterDetailGridDataSource(props.data.key);
     setDataSource(masterDetailDataSource);

apps/demos/Demos/PivotGrid/DrillDown/React/App.tsx

@@ -15,7 +15,7 @@ import { sales } from './data.ts';
 
 const App = () => {
   const [popupTitle, setPopupTitle] = useState('');
-  const [drillDownDataSource, setDrillDownDataSource] = useState<DataSource | null>(null);
+  const [drillDownDataSource, setDrillDownDataSource] = useState<DataSource | undefined>(undefined);
   const [popupVisible, setPopupVisible] = useState(false);
   const dataGridRef = useRef<DataGridRef>(null);
 

apps/demos/Demos/PivotGrid/DrillDown/ReactJs/App.js

@@ -7,7 +7,7 @@ import { sales } from './data.js';
 
 const App = () => {
   const [popupTitle, setPopupTitle] = useState('');
-  const [drillDownDataSource, setDrillDownDataSource] = useState(null);
+  const [drillDownDataSource, setDrillDownDataSource] = useState(undefined);
   const [popupVisible, setPopupVisible] = useState(false);
   const dataGridRef = useRef(null);
   const onCellClick = useCallback((e) => {