我是 React JS 的初学者，在阅读我的应用程序应用程序教程时，我看到以下错误
Failed to compile:
./src/index.js
Attempted import error: './App' does not contain a default export (imported as 'App').
为了解决这个问题，我确实在同一目录中再次创建了“my-app”项目，然后尝试启动 npm，然后遇到以下错误，请有人解释一下解决这个问题。？如果您指出我所犯的错误，那将非常有帮助。
E:\ReactJS\demo\my-app>npm start
> my-app@1.0.0 start E:\ReactJS\demo\my-app
> if-env NODE_ENV=production && npm run react-project:start:prod || npm run react-project:start:dev
> my-app@1.0.0 react-project:start:dev E:\ReactJS\demo\my-app
> eslint modules && react-project start
E:\ReactJS\demo\my-app\node_modules\eslint\lib\config\config-file.js:332
throw e;
^
Error: react-app:
Configuration for rule "array-callback-return" is invalid:
Value "warn" is the wrong type.
Referenced from: E:\ReactJS\demo\package.json
at validateRuleOptions (E:\ReactJS\demo\my-app\node_modules\eslint\lib\config\config-validator.js:102:15)
at E:\ReactJS\demo\my-app\node_modules\eslint\lib\config\config-validator.js:148:13
at Array.forEach (<anonymous>)
at Object.validate (E:\ReactJS\demo\my-app\node_modules\eslint\lib\config\config-validator.js:147:35)
at load (E:\ReactJS\demo\my-app\node_modules\eslint\lib\config\config-file.js:390:19)
at E:\ReactJS\demo\my-app\node_modules\eslint\lib\config\config-file.js:326:36
at Array.reduceRight (<anonymous>)
at applyExtends (E:\ReactJS\demo\my-app\node_modules\eslint\lib\config\config-file.js:309:28)
at Object.load (E:\ReactJS\demo\my-app\node_modules\eslint\lib\config\config-file.js:395:22)
at loadConfig (E:\ReactJS\demo\my-app\node_modules\eslint\lib\config.js:74:33)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! my-app@1.0.0 react-project:start:dev: `eslint modules && react-project start`
npm ERR! Exit status 1
不太确定这个错误，但大部分看起来都与它自己下载的包有关。
.eslintrc：
{ "extends": "rackt", "globals": { " DEV ": true }, "rules": { "react/jsx-uses-react": 1, "react/jsx-no-undef": 2, "react/wrap-multilines": 2 }, "plugins": ["react"] }
和 package.json：
{
"name": "my-app",
"version": "1.0.0",
"private": true,
"description": "",
"react-project": {
"server": "modules/server.js",
"client": "modules/client.js",
"webpack": "webpack.config.js"
},
"scripts": {
"start": "if-env NODE_ENV=production && npm run react-project:start:prod || npm run react-project:start:dev",
"test": "karma start",
"react-project:start:dev": "eslint modules && react-project start",
"react-project:start:prod": "rm -rf .build && react-project build && node .build/server.js"
},
"author": "",
"license": "ISC",
"dependencies": {
"babel-cli": "6.5.1",
"babel-core": "6.5.1",
"babel-eslint": "4.1.8",
"babel-loader": "6.2.2",
"babel-preset-es2015": "6.5.0",
"babel-preset-react": "6.5.0",
"babel-preset-react-hmre": "1.1.0",
"babel-preset-stage-1": "6.5.0",
"body-parser": "1.15.0",
"bundle-loader": "0.5.4",
"compression": "1.6.1",
"css-loader": "0.23.1",
"dotenv": "2.0.0",
"eslint": "1.10.3",
"eslint-config-rackt": "1.1.1",
"eslint-plugin-react": "3.16.1",
"expect": "1.14.0",
"express": "4.13.4",
"extract-text-webpack-plugin": "1.0.1",
"file-loader": "0.8.5",
"helmet": "1.1.0",
"hpp": "0.2.0",
"if-env": "1.0.0",
"karma": "0.13.21",
"karma-chrome-launcher": "0.2.2",
"karma-mocha": "0.2.2",
"karma-mocha-reporter": "1.2.0",
"karma-sourcemap-loader": "0.3.7",
"karma-webpack": "1.7.0",
"mocha": "2.4.5",
"morgan": "1.7.0",
"node-fetch": "1.3.3",
"null-loader": "0.1.1",
"postcss-loader": "0.8.1",
"react": "0.14.7",
"react-dom": "0.14.7",
"react-project": "0.0.30",
"react-router": "2.0.0",
"react-title-component": "1.0.1",
"source-map-support": "0.4.0",
"style-loader": "0.13.0",
"url-loader": "0.5.7",
"webpack": "1.12.14",
"webpack-dev-server": "1.14.1"
}
}