Enable HMR in dev server

app.js

@@ -42,15 +42,29 @@ app.use('/proxyUrl', function proxyRequest(req, res, next) {
 
 const webpack = require('webpack');
 const webpackConfig = require('./webpack.config.js');
+webpackConfig.plugins.push(new webpack.HotModuleReplacementPlugin());
+
+webpackConfig.entry.openmct = [
+    'webpack-hot-middleware/client',
+    webpackConfig.entry.openmct
+];
+
 const compiler = webpack(webpackConfig);
-const webpackDevRoute = require('webpack-dev-middleware')(
-    compiler, {
+
+app.use(require('webpack-dev-middleware')(
+    compiler,
+    {
         publicPath: '/dist',
         logLevel: 'warn'
     }
-);
+));
 
-app.use(webpackDevRoute);
+app.use(require('webpack-hot-middleware')(
+    compiler,
+    {
+
+    }
+));
 
 // Expose index.html for development users.
 app.get('/', function (req, res) {

package.json

@@ -67,6 +67,7 @@
     "webpack": "^4.16.2",
     "webpack-cli": "^3.1.0",
     "webpack-dev-middleware": "^3.1.3",
+    "webpack-hot-middleware": "^2.22.3",
     "zepto": "^1.2.0"
   },
   "scripts": {