react-native-dark-modeが動作しない

Question

Expo環境でreact-native-dark-modeというライブラリを使用する際にエラーが起きます。ReactNativeのバージョンが62.0以降なら対応しているはずなのですが、私の環境（Expo SDK 42.0.0）でエラーが発生します。解決方法があればお願いします。

// package.json
{
  "main": "node_modules/expo/AppEntry.js",
  "scripts": {
    "start": "expo start",
    "android": "expo start --android",
    "ios": "expo start --ios",
    "web": "expo start --web",
    "eject": "expo eject"
  },
  "dependencies": {
    "expo": "~42.0.1",
    "expo-status-bar": "~1.0.4",
    "react": "16.13.1",
    "react-dom": "16.13.1",
    "react-native": "https://github.com/expo/react-native/archive/sdk-42.0.0.tar.gz",
    "react-native-dark-mode": "^0.2.2",
    "react-native-web": "~0.13.12"
  },
  "devDependencies": {
    "@babel/core": "^7.9.0"
  },
  "private": true
}

// App.js
import { StatusBar } from 'expo-status-bar';
import React from 'react';
import { StyleSheet, Text, View } from 'react-native';
import { useDarkMode } from 'react-native-dark-mode';

export default function App() {

  const isDarkMode = useDarkMode(); // 追記箇所

  return (
    <View style={styles.container}>
      <Text>Open up App.js to start working on your app!</Text>
      <StatusBar style="auto" />
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center',
  },
});

// エラーログ
TypeError: null is not an object (evaluating '_nativeModule.NativeModule.initialMode')
at node_modules\react-native\Libraries\LogBox\LogBox.js:148:8 in registerError
at node_modules\react-native\Libraries\LogBox\LogBox.js:59:8 in errorImpl
at node_modules\react-native\Libraries\LogBox\LogBox.js:33:4 in console.error
at node_modules\expo\build\environment\react-native-logs.fx.js:27:4 in error
at node_modules\react-native\Libraries\Core\ExceptionsManager.js:104:6 in reportException
at node_modules\react-native\Libraries\Core\ExceptionsManager.js:171:19 in handleException
at node_modules\react-native\Libraries\Core\setUpErrorHandling.js:24:6 in handleError
at node_modules\expo-error-recovery\build\ErrorRecovery.fx.js:12:21 in ErrorUtils.setGlobalHandler$argument_0
at node_modules\regenerator-runtime\runtime.js:63:36 in tryCatch
at node_modules\regenerator-runtime\runtime.js:294:29 in invoke
at node_modules\regenerator-runtime\runtime.js:63:36 in tryCatch
at node_modules\regenerator-runtime\runtime.js:155:27 in invoke
at node_modules\regenerator-runtime\runtime.js:165:18 in PromiseImpl.resolve.then$argument_0
at node_modules\react-native\node_modules\promise\setimmediate\core.js:37:13 in tryCallOne
at node_modules\react-native\node_modules\promise\setimmediate\core.js:123:24 in setImmediate$argument_0
at node_modules\react-native\Libraries\Core\Timers\JSTimers.js:130:14 in _callTimer
at node_modules\react-native\Libraries\Core\Timers\JSTimers.js:181:14 in _callImmediatesPass
at node_modules\react-native\Libraries\Core\Timers\JSTimers.js:441:30 in callImmediates
at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:387:6 in __callImmediates
at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:135:6 in __guard$argument_0
at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:364:10 in __guard
at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:134:4 in flushedQueue
at [native code]:null in flushedQueue
at [native code]:null in invokeCallbackAndReturnFlushedQueue

Answer 1

githubのrequirementにxcode11とありました。恐らくexpoでは使えないかと思いますが、代わりにreact-native-appearanceというライブラリで同じことができたので、expoの使用者はこちらを使うと良いと思います。