First of all, I’m very happy to hear that Hanami team is considering Webpack. Webpack is an awesome tool to bundle/process assets.
I’ve created the hanami-webpack, a very experimental and hacky gem to run Webpack with Hanami, but it’s important to tell that I just followed some principles that I saw in https://github.com/mipearson/webpack-rails.
The answers to your questions:
In my gem I used the Webpack’s StatsPlugin
to expose, through a JSON manifest, the path for my [webpack entry points] (http://webpack.github.io/docs/configuration.html#entry), so the Hanami can download this manifest in order to figure out the paths for the entries.
Here some key points about the implementation:
About the server, I totally agree with you about the smooth integration between webpack dev server and Hanami, in my gem I made a monkey patch on the Hanami::DevServer.start to spawn a process with the webpack dev server https://github.com/samuelsimoes/hanami-webpack/blob/master/lib/hanami_webpack/dev_server.rb#L7 to make the dev server integration transparent, I don’t know if it’s a good idea, just sounded good for me.
I’m not a specialist in Webpack or Hanami, but I’m glad to help you guys on this topic.