Replaced uglifyjs w/ webpack 5 TerserPlugin.

config/webpack.config.prod.js

@@ -6,7 +6,8 @@ const webpack = require("webpack");
 const merge = require("webpack-merge");
 const OptimizeCSSAssetsPlugin = require("optimize-css-assets-webpack-plugin");
 const MiniCSSExtractPlugin = require("mini-css-extract-plugin");
-const UglifyJSPlugin = require("uglifyjs-webpack-plugin");
+const TerserPlugin = require("terser-webpack-plugin");
+
 const helpers = require("./helpers");
 const commonConfig = require("./webpack.config.common");
 const isProd = process.env.NODE_ENV === "production";
@@ -33,16 +34,15 @@ const webpackConfig = merge(commonConfig(false), {
         }
       }
     },
+    minimize: true,
     minimizer: [
       new OptimizeCSSAssetsPlugin({
         cssProcessorPluginOptions: {
           preset: ["default", { discardComments: { removeAll: true } }]
         }
       }),
-      new UglifyJSPlugin({
-        cache: true,
-        parallel: false,
-        sourceMap: !isProd
+      new TerserPlugin({
+        test: /\.js(\?.*)?$/i,
       })
     ]
   },