1.只用cnpm
2重装node_modules
3webpack要兼容
cnpm uninstall webpack -g
cnpm uninstall -g webpack-dev-server
//安装指定版本
cnpm install webpack@3.8.0 --save-dev
cnpm install webpack-dev-server@2.9.7 --save-dev
4 idea miss dev 解决方法输入vue init webpack 将package.json中丢失的：
"dev": "webpack-dev-server --inline --progress --config build/webpack.dev.conf.js",
"start": "npm run dev",
"build": "node build/build.js"