Add optimize-css-assets plugin

Author: Spring3

package-lock.json

@@ -43,11 +43,11 @@
     "history": "^4.7.2",
     "html-webpack-plugin": "^2.28.0",
     "jest": "^22.4.3",
+    "optimize-css-assets-webpack-plugin": "^3.2.0",
     "postcss": "^6.0.21",
     "postcss-loader": "^2.1.4",
     "prop-types": "^15.6.1",
     "purgecss-webpack-plugin": "^0.22.0",
-    "react-mock-router": "^1.0.15",
     "react-test-renderer": "^16.3.2",
     "redux-mock-store": "^1.5.1",
     "style-loader": "^0.19.0",

package.json

@@ -4,6 +4,7 @@ const HtmlWebpackPlugin = require('html-webpack-plugin');
 const ExtractTextPlugin = require('extract-text-webpack-plugin');
 const PurgecssPlugin = require('purgecss-webpack-plugin');
 const NodeExternals = require('webpack-node-externals');
+const OptimizeCssPlugin = require('optimize-css-assets-webpack-plugin');
 const glob = require('glob-all');
 // const { BundleAnalyzerPlugin } = require('webpack-bundle-analyzer');
 
@@ -81,6 +82,9 @@ module.exports = {
         comments: false
       }
     }),
+    new OptimizeCssPlugin({
+      cssProcessorOptions: { discardComments: { removeAll: true } }
+    }),
     new PurgecssPlugin({
       paths: glob.sync([
         SRC_DIR + '/index.html',