Use webpack-merge.

Move html export config to own file.
Delete unnecessary config options.
Use cheap source maps.

Signed-off-by: David Mehren <dmehren1@gmail.com>

webpack.htmlexport.js

@@ -0,0 +1,25 @@
+const MiniCssExtractPlugin = require('mini-css-extract-plugin')
+const path = require('path')
+
+module.exports = {
+  name: 'save-as-html',
+  entry: {
+    htmlExport: path.join(__dirname, 'public/js/htmlExport.js')
+  },
+  module: {
+    rules: [{
+      test: /\.css$/,
+      use: [MiniCssExtractPlugin.loader, 'css-loader']
+    }]
+  },
+  output: {
+    path: path.join(__dirname, 'public/build'),
+    publicPath: '/build/',
+    filename: '[name].js'
+  },
+  plugins: [
+    new MiniCssExtractPlugin({
+      filename: 'html.min.css'
+    })
+  ]
+}