修复webpack自动刷新页面慢的问题

新建.babelrc文件，配置如下

{
  "presets": [
    "es2015"
  ],
  "ignore":[
    "react-router-dom.js",
    "react-dom.js",
    "react.js",
    "webpack-dev-server.js",
    "webpack.js",
    "react-responsive.js"
  ]
}

在“ignore”里面输入，引入的一些包。亲测，有效~