npm install webpack-dev-server -g 

npm install webpack-dev-server --save-dev

 module.exports = {
 entry:"./js/index.js",
 output:{
 path:"/", 
 //注意這里的改變，必須是根目錄,指定目錄無效，因為webpack會在內存中根目錄下生成下面文件名。
 filename:"bundle.js"
 },
 module:{
 loaders:[
 { test:/\.css$/,loader:'style-loader'},
 { test:/\.css$/,loader:'css-loader'}
 ]
 },
 resolve:{
 extensions:['.vue','.js',".css",'jsx'] //自動補全識別后綴
 }
 }

<script type="text/javascript" src="bundle.js"></script>

webpack-dev-server --hot --inline