Use Terser plugin to minimize and build source-map

Upgraded Webpack

Author: pascalgagneur

package.json

@@ -78,8 +78,7 @@
     "react-test-renderer": "^16.0.0",
     "sinon": "^7.1.0",
     "styled-components": "^4.1.3",
-    "uglifyjs-webpack-plugin": "^0.4.6",
-    "webpack": "^4.23.1",
+    "webpack": "^4.29.6",
     "webpack-bundle-analyzer": "^2.13.1",
     "webpack-cli": "^3.1.2",
     "webpack-dev-server": "^3.1.10"

webpack.config.prod.js

@@ -1,15 +1,29 @@
 const path = require('path');
 const CleanWebpackPlugin = require('clean-webpack-plugin');
-const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
+const TerserPlugin = require('terser-webpack-plugin');
 const { BundleAnalyzerPlugin } = require('webpack-bundle-analyzer');
 
 module.exports = {
   mode: 'production',
+  devtool: 'source-map',
   entry: path.resolve(__dirname, 'lib/index'),
   externals: {
     'styled-components': 'styled-components',
     react: 'react'
   },
+  optimization: {
+    minimizer: [
+      new TerserPlugin({
+        parallel: true,
+        sourceMap: true,
+        terserOptions: {
+          output: {
+            comments: false,
+          }
+        },
+      }),
+    ]
+  },
   output: {
     path: path.resolve(__dirname, 'dist'),
     filename: 'react-simple-chatbot.js',
@@ -23,10 +37,7 @@ module.exports = {
   },
   plugins: [
     new CleanWebpackPlugin(['dist']),
-    new UglifyJsPlugin({
-      comments: false
-    }),
-    process.env.BUNDLE_ANALYZE === 'true' ? new BundleAnalyzerPlugin() : () => {}
+    process.env.BUNDLE_ANALYZE === 'true' ? new BundleAnalyzerPlugin() : () => { }
   ],
   module: {
     rules: [