Here is the process in short:

Compile the server code with webpack
Use target: "node" or target: "async-node"
Enabled HMR via --hot or HotModuleReplacementPlugin
Use webpack/hot/poll or webpack/hot/signal
The first polls the fs for updates (easy to use)
The second listens for a process event to check for updates (you need a way to send the signal)
Run the bundle with node.
You can't use existing HMR loaders like react-hot-loader or style-loader because they make no sense in a server environment. Just add manuall replacement code at the correct location (i. e. accept request handler like in the example)

You can't use the webpack-dev-server. It's a server which serves assets not a runner. Just run webpack --watch and node bundle.js. I would go the webpack/hot/poll?1000 route first. It's pretty easy to use and suitable for dev environments. For production (if you want to hot update your production server) the signal approach is better suited.

webpack = require 'webpack'

module.exports =
 entry: [
  'webpack/hot/poll?1000' # <-- 輪詢更新內(nèi)容的代碼
  './src/main' # <-- 項目入口
 ]
 target: 'node' # <-- 指明編譯方式為 node
 output:
  path: 'build/'
  filename: 'bundle.js' # <-- 編譯結(jié)果的文件名
 module:
  loaders: [
   {test: /\.coffee/, loader: 'coffee'}
  ]
 plugins: [
  new webpack.HotModuleReplacementPlugin() # <-- 照常啟動 hot mode
 ]
 resolve:
  extensions: ['.js', '', '.coffee']

npm i
webpack --watch & # <-- watch 模式
node build/bundle.js # <-- 運行的是打包結(jié)果的代碼

exports.data = 'code 5'

exports.printSelf = ->
 console.log 'doing 3'

lib = require './lib'

console.log lib.data
lib.printSelf()

counter = 0
setInterval ->
 counter += 1
 console.log counter
, 2000

if module.hot
 module.hot.accept './lib', ->
  lib = require './lib'

  console.log lib.data
  lib.printSelf()

➤➤ cat build/0.c797c084381bfeac37f7.hot-update.js
exports.id = 0;
exports.modules = {

/***/ 3:
/***/ function(module, exports, __webpack_require__) {

  var counter, lib;
  lib = __webpack_require__(4);
  console.log(lib.data);
  lib.printSelf();
  counter = 0;
  setInterval(function() {
   counter += 1;
   return console.log(counter, 3);
  }, 2000);

  if (true) {
   module.hot.accept(4, function() {
    lib = __webpack_require__(4);
    console.log(lib.data);
    return lib.printSelf();
   });
  }

/***/ }
};