Use optimization.minimizer syntax

Author: mike-marcacci

README.md

@@ -68,20 +68,30 @@ module.exports = {
 
 ### Minimizing For Production
 
-While webpack 5 is likely to come with a CSS minimizer built-in, with webpack 4 you need to bring your own. To minify the output, use a plugin like [optimize-css-assets-webpack-plugin](https://github.com/NMFR/optimize-css-assets-webpack-plugin):
+While webpack 5 is likely to come with a CSS minimizer built-in, with webpack 4 you need to bring your own. To minify the output, use a plugin like [optimize-css-assets-webpack-plugin](https://github.com/NMFR/optimize-css-assets-webpack-plugin). Setting `optimization.minimizer` overrides the defaults provided by webpack, so make sure to also specify a JS minimizer:
 
 **webpack.config.js**
 
 ```js
+const UglifyJsPlugin = require("uglifyjs-webpack-plugin");
 const MiniCssExtractPlugin = require("mini-css-extract-plugin");
 const OptimizeCSSAssetsPlugin = require("optimize-css-assets-webpack-plugin");
 module.exports = {
+  optimization: {
+    minimizer: [
+      new UglifyJsPlugin({
+        cache: true,
+        parallel: true,
+        sourceMap: true // set to true if you want JS source maps
+      }),
+      new OptimizeCSSAssetsPlugin({})
+    ]
+  },
   plugins: [
     new MiniCssExtractPlugin({
       filename: "[name].css",
       chunkFilename: "[id].css"
-    }),
-    new OptimizeCssAssetsPlugin()
+    })
   ],
   module: {
     rules: [