bundling refactor

common/getBundleExternals.js

@@ -0,0 +1,10 @@
+const volatilePackages = require('./volatilePackages');
+
+function getBundleExternals() {
+  return volatilePackages.reduce((acc, item) => {
+    acc[item] = `commonjs ${item}`;
+    return acc;
+  }, {});
+}
+
+module.exports = getBundleExternals;