博览会-根据需要反应本机文件系统错误

Question

我不需要react-native-fs，应用会引发异常：

'main' has not been registered. This can happen if: 
* Metro (the local dev server) is run from the wrong folder. Check if Metro is running, stop it and restart it in the current project. 
* A module failed to load due to an error and `AppRegistry.registerComponent` wasn't called.

我按照官方文档中的指南进行安装。

App.js：

import React from 'react';
import { View } from 'react-native';

const RNFS = require("react-native-fs");

export default function App() {
  return (

    <View>

    </View>

  );
}

package.json：

{
  "main": "index.js",
  "scripts": {
    "android": "react-native run-android",
    "ios": "react-native run-ios",
    "web": "expo start --web",
    "start": "react-native start",
    "test": "jest"
  },
  "dependencies": {
    "expo": "~39.0.2",
    "expo-splash-screen": "~0.6.0",
    "expo-status-bar": "~1.0.2",
    "expo-updates": "~0.3.2",
    "react": "16.13.1",
    "react-dom": "16.13.1",
    "react-native": "~0.63.2",
    "react-native-fs": "^2.16.6",
    "react-native-gesture-handler": "~1.7.0",
    "react-native-reanimated": "~1.13.0",
    "react-native-screens": "~2.10.1",
    "react-native-unimodules": "~0.11.0",
    "react-native-web": "~0.13.12"
  },
  "devDependencies": {
    "@babel/core": "~7.9.0",
    "babel-jest": "~25.2.6",
    "jest": "~25.2.6",
    "react-test-renderer": "~16.13.1"
  },
  "jest": {
    "preset": "react-native"
  },
  "private": true
}

很明显，如果我删除了require行，则错误消失了。