从'react'导入React导致Uncaught SyntaxError：意外的标识符

Question

我已经与babel一起安装了webpack 3，并且我的条目index.js/bundle.js将构建并运行，我已经使用ES7 / 8功能对其进行了测试，但是导入无法正常工作，并导致Uncaught SyntaxError: Unexpected identifier。我尝试将babel config放在应用程序根目录的package.json以及一个单独的.babelrc文件中，但是尝试导入时仍然出现错误。我是否缺少包裹或设置？

index.js（有效）

// does not work
// import React from 'react' 

// works
const object1 = {
  a: 'somestring',
  b: 42,
  c: false
};

console.log(Object.values(object1));

webpack.config.js

const path = require('path')

module.exports = {
  context: path.resolve(__dirname, 'app/assets/javascripts/source'),
  entry: './index.js',
  output: {
    filename: 'bundle.js',
    path: path.resolve(__dirname, 'app/assets/javascripts/webpack')
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env']
          }
        }
      }
    ]
  }
}

.babelrc

{
  "presets": ["env", "react"]
}

package.json

}
  ...
  "license": "MIT",
  "scripts": {
    "build": "webpack",
  },
  "babel": {
    "presets": [
      "env",
      "react"
    ]
  },
  "devDependencies": {
    "babel-core": "^6.26.0",
    "babel-loader": "^7.1.2",
    "babel-preset-env": "^1.6.1",
    "babel-preset-react": "^6.24.1",
    "prop-types": "^15.6.0",
    "react": "^16.2.0",
    "react-dom": "^16.2.0",
    "webpack": "^3.10.0",
    "webpack-dev-server": "^2.11.1"
  }
}

Answer 1

试试这个：transform-es2015-modules-amd，这个插件将 ES2015 模块转换为异步模块定义（AMD）。

{
    presets: ["env", "react"],
    plugins: ["transform-es2015-modules-amd"]
 }

更多信息请参见 transform-es2015-modules-amd