text: import React, { useState } from 'react';
  import { StyleSheet, Text, View } from 'react-native';
  import WelcomeScreen from './screens/WelcomeScreen'
  import RateScreen from './screens/RateScreen'
  import * as Font from 'expo-font'
  import { AppLoading } from 'expo';
  import { createAppContainer ,createSwitchNavigator } from 'react-navigation';
  import { AppDrawerNavigator } from './components/AppDrawerNavigator'
  import { AppTabNavigator } from './components/AppTabNavigator'
  import {decode, encode} from 'base-64'
  
  if (!global.btoa) {  global.btoa = encode }
  
  if (!global.atob) { global.atob = decode }
  
  
  
  const getFonts = () => Font.loadAsync({
    'pacifico-regular': require('./assets/fonts/Pacifico-Regular.ttf'),
    'FredokaOne-Regular': require('./assets/fonts/FredokaOne-Regular.ttf')
  })
  
  export default function App() {
    const [fontsLoaded, steFontsLoaded] = useState(false)
  
    if (fontsLoaded){
      return (
        <AppContainer/>
      );
    } else {
      return (
        <AppLoading
        startAsync = {getFonts}
        onFinish = {()=> steFontsLoaded(true)}
        />
      );
  
    }
    
  }
  
  const switchNavigator = createSwitchNavigator({
    WelcomeScreen:{screen: WelcomeScreen},
    Drawer:{screen: AppDrawerNavigator},
    BottomTab: {screen: AppTabNavigator},
  })
  
  const AppContainer = createAppContainer(switchNavigator)
  