feat($config): Enable dead code elimination and tell UglifyJS about the pure functions from Elm

Author: halfzebra

config/webpack.config.prod.js

@@ -183,7 +183,27 @@ module.exports = {
     // Minify the compiled JavaScript.
     new UglifyJsPlugin({
       compress: {
-        warnings: false
+        warnings: false,
+        dead_code: true,
+        pure_funcs: [
+          '_elm_lang$core$Native_Utils.update',
+          'A2',
+          'A3',
+          'A4',
+          'A5',
+          'A6',
+          'A7',
+          'A8',
+          'A9',
+          'F2',
+          'F3',
+          'F4',
+          'F5',
+          'F6',
+          'F7',
+          'F8',
+          'F9'
+        ]
       },
       output: {
         comments: false