Hot reload webpack configuration

webpack.config.js

var Webpack = require("webpack");
var path = require("path");
var util = require("util");

var host = process.env.HOST || "localhost";
var port = process.env.PORT || 8080;

module.exports = {
  entry: {
    app: [
      "webpack/hot/only-dev-server",
      "./app/main.jsx"
    ],
    widget: [
      "./app/widget.jsx"
    ]
  },
  output: {
    path: path.resolve(__dirname, "public", "dist", "js"),
    publicPath: util.format("http://%s:%s/", host, port),
    filename: "[name].bundle.js",
    chunkFilename: "[name]-[id].bundle.js"
  },
  module: {
    loaders: [{
        test: /\.jsx$/,
        loaders: ["react-hot", "babel-loader"],
        exclude: path.resolve(__dirname, "node_modules")
      }, {
        test: /\.json$/,
        loader: "json-loader"
      }, {
        test: /\.scss$/,
        loader: "style!css!sass"
      },
      // Needed for the css-loader when [bootstrap-webpack](https://github.com/bline/bootstrap-webpack)
      // loads bootstrap's css.
      { test: /\.woff2?(\?v=\d+\.\d+\.\d+)?$/, loader: "url?limit=10000&minetype=application/font-woff" },
      { test: /\.ttf(\?v=\d+\.\d+\.\d+)?$/,    loader: "url?limit=10000&minetype=application/octet-stream" },
      { test: /\.eot(\?v=\d+\.\d+\.\d+)?$/,    loader: "file" },
      { test: /\.svg(\?v=\d+\.\d+\.\d+)?$/,    loader: "url?limit=10000&minetype=image/svg+xml" }
    ]
  },
  resolve: {
    extensions: ["", ".js", ".jsx"],
    alias: {
      pubnub: path.resolve(__dirname, "./lib/pubnub")
    }
  },
  devServer: {
    contentBase: path.resolve(__dirname, "public"),
    devtool: "eval",
    progress: true,
    colors: true,
    hot: true,
    host: "0.0.0.0",
    port: port,
    proxy: {
      "*": util.format("http://%s:8081", host)
    }
  },
  plugins: [
    new Webpack.HotModuleReplacementPlugin(),
    new Webpack.NoErrorsPlugin()
  ]
};