解决Webpack dev server热加载失败的publicPath配置问题

XMLHttpRequest cannot load http://localhost:8080/dist/06854fc8988da94501a9.hot-update.json. 
No 'Access-Control-Allow-Origin' header is present on the requested resource. 
Origin 'http://localhost' is therefore not allowed access.

dev-server.js:37 [HMR] Update failed: Error: Manifest request to http://localhost:8080/dist/06854fc8988da94501a9.hot-update.json timed out.
 at XMLHttpRequest.request.onreadystatechange (http://localhost:8080/dist/main.js:38:22)

output : {
 filename : '[name].js',
 // 不可配置为绝对路径,这是错误的配置
 //publicPath: "http://localhost:8080/dist/",

 // 这是正确的配置，
 publicPath: "/dist/",
 path : build,
 // umd包含了对amd、commonjs、var等多种规范的支持 
 libraryTarget : 'var' 
}