App.js 코드스니펫 복붙하고 실행했더니 에러가 납니다.

작성한 코드 및 에러 메세지

import React, { useEffect } from 'react';

//이제 모든 페이지 컴포넌트들이 끼워져있는 책갈피를 메인에 둘예정이므로

//컴포넌트를 더이상 불러오지 않아도 됩니다.

// import MainPage from './pages/MainPage';

// import DetailPage from './pages/DetailPage';

import { StatusBar } from 'expo-status-bar';

//메인에 세팅할 네비게이션 도구들을 가져옵니다.

import {NavigationContainer} from '@react-navigation/native';

import StackNavigator from './navigation/StackNavigator'

import mobileAds from 'react-native-google-mobile-ads';

export default function App() {

  console.disableYellowBox = true;

  useEffect(()=>{

    //구글 애드몹은 실제 빌드된 앱에서만 가능하기 때문에! 조건부 처리!

    if(!__DEV__){

      mobileAds()

      .initialize()

      .then(adapterStatuses => {

        // Initialization complete!

      });

    }

  },[])

  return (

  <NavigationContainer>

    <StatusBar style="black" />

    <StackNavigator/>

 </NavigationContainer>);

}

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Invariant Violation: Your JavaScript code tried to access a native module that doesn't exist. 

If you're trying to use a module that is not supported in Expo Go, you need to create a development build of your app. See https://docs.expo.dev/development/introduction/ for more info.

at node_modules\react-native\Libraries\Core\ExceptionsManager.js:null in reportException

at node_modules\react-native\Libraries\Core\ExceptionsManager.js:null in handleException

at node_modules\react-native\Libraries\Core\setUpErrorHandling.js:null in handleError

at node_modules\expo\build\errors\ExpoErrorManager.js:null in errorHandler

at node_modules\expo\build\errors\ExpoErrorManager.js:null in <anonymous>

at node_modules\@react-native\polyfills\error-guard.js:null in ErrorUtils.reportFatalError

at node_modules\metro-runtime\src\polyfills\require.js:null in guardedLoadModule

at node_modules\metro-runtime\src\polyfills\require.js:null in runUpdatedModule

at node_modules\metro-runtime\src\polyfills\require.js:null in metroHotUpdateModule

at node_modules\metro-runtime\src\polyfills\require.js:null in define

at node_modules\metro-runtime\src\modules\HMRClient.js:null in inject

at node_modules\metro-runtime\src\modules\HMRClient.js:null in injectUpdate

at node_modules\metro-runtime\src\modules\HMRClient.js:null in on$argument_1

at node_modules\metro-runtime\src\modules\vendor\eventemitter3.js:null in emit

at node_modules\metro-runtime\src\modules\HMRClient.js:null in _ws.onmessage

at node_modules\event-target-shim\dist\event-target-shim.js:null in EventTarget.prototype.dispatchEvent

at node_modules\react-native\Libraries\WebSocket\WebSocket.js:null in _eventEmitter.addListener$argument_1

at node_modules\react-native\Libraries\vendor\emitter\EventEmitter.js:null in emit

at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:null in __callFunction

at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:null in __guard$argument_0

at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:null in __guard

at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:null in callFunctionReturnFlushedQueue