React Webpack babel7无法解析es6样式函数赋值

我正在学习React（udemy course） . 我陷入了一个兔子洞试图升级我的课程项目，以使用ES6样式函数声明和赋值 . 是的，我试图找到一个类似的问题，但没有找到任何有效的 .

这是我的package.json：

{
  "name": "redux-simple-starter",
  "version": "1.0.0",
  "description": "Simple starter package for Redux with React and Babel support",
  "main": "index.js",
  "repository": "git@github.com:StephenGrider/ReduxSimpleStarter.git",
  "scripts": {
    "start": "node ./node_modules/webpack-dev-server/bin/webpack-dev-server.js",
    "test": "mocha --compilers js:babel-core/register --require ./test/test_helper.js --recursive ./test",
    "test:watch": "npm run test -- --watch",
    "build": "webpack -p --define process.env.NODE_ENV='\"production\"' --progress --colors"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@babel/core": "7.0.0",
    "@babel/preset-env": "^7.1.0",
    "@babel/preset-react": "^7.0.0",
    "babel-core": "^6.26.3",
    "babel-loader": "^8.0.4",
    "babel-preset-env": "^1.7.0",
    "webpack": "^2.7.0",
    "webpack-dev-server": "^1.16.5"
  },
  "dependencies": {
    "lodash": "^3.10.1",
    "react": "16.3.2",
    "react-dom": "16.3.2",
    "react-redux": "5.0.7",
    "redux": "4.0.0",
    "yarn": "^1.10.1",
    "youtube-api-search": "0.0.5"
  }
}

和我的.babelrc文件：

{
  "presets": ["@babel/preset-env", "@babel/preset-react"]
}

还有我的webpack.config.js：

module.exports = {
  entry: ['./src/index.js'],
  output: {
    path: __dirname,
    publicPath: '/',
    filename: 'bundle.js'
  },
  module: {
    loaders: [
      {
        exclude: /node_modules/,
        loader: 'babel-loader',
        options: {
          presets: ["@babel/preset-env","@babel/preset-react"]
        }
      }
    ]
  },
  resolve: {
    extensions: ['.js', '.jsx']
  },
  devServer: {
    historyApiFallback: true,
    contentBase: './',
    watchOptions: {
      aggregateTimeout: 300,
      poll: 1000
    }
  }
};

主index.js文件如下所示：

import React from 'react';
import ReactDOM from 'react-dom';
import SearchBar from './components/search_bar';

const API_KEY = 'xxx';

const App = function() {
  return (
    <div>
      <SearchBar />
    </div>
  );
}
ReactDOM.render(
  <App />, document.querySelector('.container'));

最后，search_bar.js文件如下所示：

import React from 'react';

const SearchBar = () ==> {
  return <input />;
}

export default SearchBar;

我已经完成了npm安装等，但是当我使用npm start运行应用程序时，我收到一个错误：

./src/components/search_bar.js中的错误模块构建失败：SyntaxError：/Users/xxxxx/ReactProjects/ReduxSimpleStarter/src/components/search_bar.js：意外的令牌（3:19）

1 |从'react'中导入React; 2 |

3 | const SearchBar =（）==> {| ^ 4 |回归; 5 | } 6 |在_class.raise（/Users/xxxxx/ReactProjects/ReduxSimpleStarter/node_modules/@babel/parser/lib/index.js:3939:15）_class.unexpected（/ Users / xxxxx / ReactProjects / ReduxSimpleStarter / node_modules / @ babel /在_class.parseExprAtom（/ Users /xxxxx/ReactProjects/ReduxSimpleStarter/node_modules/@babel/parser/lib/index.js:6284:21）在_class.parseExprAtom（/Users/xxxxx/ReactProjects/ReduxSimpleStarter/node_modules/@babel/parser/lib/index.js ：3635：52）_class.parseExprSubscripts（/Users/xxxxx/ReactProjects/ReduxSimpleStarter/node_modules/@babel/parser/lib/index.js:5924:21）_class.parseMaybeUnary（/ Users / xxxxx / ReactProjects / ReduxSimpleStarter / node_modules/@babel/parser/lib/index.js：5903：21）在_class.parseExprOps（/Users/xxxxx/ReactProjects/ReduxSimpleStarter/node_modules/@babel/parser/lib/index.js:5812:21）_class .parseMaybeCon在_class.parseMaybeAssign（/ Users / xxxxx / ReactProjects / ReduxSimpleStarter / node_modules / @ babel / parser / lib）中的ditional（/Users/xxxxx/ReactProjects/ReduxSimpleStarter/node_modules/@babel/parser/lib/index.js:5784:21） /index.js:5731:21）@ ./src/index.js 3：0-48 @ multi ./src/index.js webpack：编译失败 .

任何人都可以帮助解释这里出了什么问题，为什么它不起作用？谢谢 .