React Native) splash screen(로딩화면)

export default class App extends React.Component {
state = {
isLoading: true,
};
componentDidMount = async () => {
setTimeout(() => {
this.setState({ isLoading: false });
}, 3000);
};

render() {
if (this.state.isLoading) {
return ;
} else {
return (

<Stack.Navigator
initialRouteName="Login"
screenOptions={{
headerShown: false,
}}
>