Cannot assign to read only property ‘exports‘ of object ‘#＜Object＞‘

webpack打包js文件中不允许混用import和module.exports。

方式①：babel.config.js添加sourceType:

{"presets": [...],"sourceType": "unambiguous"
}

方式②：安装babel-plugin-transform-es2015-modules-commonjs

npm install babel-plugin-transform-es2015-modules-commonjs

.babelrc文件配置 

{"presets": [...],"plugins":["transform-es2015-modules-commonjs"]
}