Webpack 接受五个最基础的配置项，分别是：

    • entry
    • output
    • loaders
    • plugins
    • mode

    Because webpack expects absolute paths for many configuration options such as __dirname + '/app/folder' the Windows \ path separator can break some functionality. Use the correct separators. I.e. path.resolve(__dirname, 'app/folder') or path.join(__dirname, 'app', 'folder').