Update to use terser 4 and remove deprecated webpack uglify minifer per

webpack-contrib/terser-webpack-plugin#335 (comment)

package.json

@@ -28,6 +28,7 @@
     "babel-eslint": "^10.0.3",
     "babel-loader": "^8.0.6",
     "core-js": "2",
+    "terser-webpack-plugin": "4.2.3",
     "css-loader": "^3.4.1",
     "eslint": "^6.8.0",
     "eslint-config-airbnb": "^18.0.1",
@@ -42,7 +43,6 @@
     "prettier": "^1.19.1",
     "style-loader": "^1.1.2",
     "stylelint-config-recommended": "^3.0.0",
-    "uglifyjs-webpack-plugin": "^2.2.0",
     "webpack": "^4.41.5",
     "webpack-cli": "^3.3.10",
     "webpack-dev-server": "^3.10.1"

webpack.config.js

@@ -1,5 +1,5 @@
 const path = require('path');
-const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
+const TerserPlugin = require('terser-webpack-plugin');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
 const MiniCssExtractPlugin = require('mini-css-extract-plugin');
 
@@ -53,9 +53,8 @@ module.exports = {
     contentBase: path.join(__dirname, 'public'),
   },
   optimization: {
-    // via https://stackoverflow.com/questions/49053215/webpack-4-how-to-configure-minimize
-    minimizer: [new UglifyJsPlugin()],
-    noEmitOnErrors: true,
+    minimize: true,
+    minimizer: [new TerserPlugin()],
   },
   plugins: [
     // via https://www.netlify.com/blog/2017/11/30/starting-with-webpack-from-scratch/