Webpack dev server熱載入失敗的解決辦法
利用Webpack dev server作為熱載入伺服器時,出現以下錯誤:
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.
或者出現以下的警告資訊:
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)
經過診斷,配置錯誤的地方在於webpack.config.js的publicPath,需要將絕對地址改為相對地址,如下:
output : {
filename : '[name].js',
// 不可配置為絕對路徑,這是錯誤的配置
//publicPath: "http://localhost:8080/dist/",
// 這是正確的配置,
publicPath: "/dist/",
path : build,
// umd包含了對amd、commonjs、var等多種規範的支援
libraryTarget : 'var'
}
經過反覆的測試,將webpack dev server的publicPath注入到其他域下,如果使用絕對地址配置,一定會出現上述錯誤。
需要特別注意的是,webpack dev server與webpack-hot-middleware剛好相反,webpack-hot-middleware必須使用絕對地址。