including polyfills in production build (#562)

Author: Ben Hamlin

packages/razzle/config/createConfig.js

@@ -434,9 +434,15 @@ module.exports = (
         // runtimeChunk: true,
       };
     } else {
-      // Specify production entry point (just /client/index.js)
+      // Specify production entry point (/client/index.js)
       config.entry = {
-        client: [paths.appClientIndexJs],
+          client: [
+            // We ship a few polyfills by default but only include them if React is being placed in
+            // the default path. If you are doing some vendor bundling, you'll need to require the razzle/polyfills
+            // on your own.
+            !!dotenv.raw.REACT_BUNDLE_PATH && require.resolve('./polyfills'),
+            paths.appClientIndexJs
+          ],
       };
 
       // Specify the client output directory and paths. Notice that we have