update demo-react-switch-tabs,

03_source/mobile/src/pages/DemoReactSwitchTabs/AppPages/Tab1.tsx

@@ -17,7 +17,7 @@ import { chevronBackOutline, refreshOutline } from 'ionicons/icons';
 
 import './Tab1.css';
 
-const Tab1 = () => {
+const Tab1 = (): React.JSX.Element => {
   const router = useIonRouter();
 
   function handleBackClick() {

03_source/mobile/src/pages/DemoReactSwitchTabs/AppPages/Tab2.tsx

@@ -2,7 +2,7 @@ import { IonContent, IonHeader, IonPage, IonTitle, IonToolbar } from '@ionic/rea
 import ExploreContainer from '../components/ExploreContainer';
 import './Tab2.css';
 
-const Tab2 = () => {
+const Tab2 = (): React.JSX.Element => {
   return (
     <IonPage>
       <IonHeader>

03_source/mobile/src/pages/DemoReactSwitchTabs/AppPages/Tab3.tsx

@@ -2,7 +2,7 @@ import { IonContent, IonHeader, IonPage, IonTitle, IonToolbar } from '@ionic/rea
 import ExploreContainer from '../components/ExploreContainer';
 import './Tab3.css';
 
-const Tab3 = () => {
+const Tab3 = (): React.JSX.Element => {
   return (
     <IonPage>
       <IonHeader>