index.js

import { registerRootComponent } from 'expo';

import React from 'react';
import App from './src/App';
import { Provider } from 'react-redux';
import { createStore, applyMiddleware, compose } from 'redux'
import promiseMiddleware from 'redux-promise';
import reducers from './src/store/reducers';
import { DarkTheme ,Provider as PaperProvider } from 'react-native-paper';
import Toast from 'react-native-toast-message';
import {View,Text} from 'react-native';

const composeEnhancers = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ || compose;
const createStoreWithMiddleware = createStore(
    reducers,
    composeEnhancers(applyMiddleware(promiseMiddleware))
)

const toastConfig = {
    info: (internalState) => (
      <View style={{ height: 60, width: '100%', backgroundColor: 'pink' }}>
        <Text>{internalState.text1}</Text>
      </View>
    )   
}

const reduxApp = () => (
    <Provider store={createStoreWithMiddleware}>
        <PaperProvider>
            <App/>
            <Toast config={toastConfig} ref={(ref) => Toast.setRef(ref)} />
        </PaperProvider>
    </Provider>
)

// registerRootComponent calls AppRegistry.registerComponent('main', () => reduxApp);
// It also ensures that whether you load the app in the Expo client or in a native build,
// the environment is set up appropriately
registerRootComponent(reduxApp);