diff --git a/src/renderers/dom/client/__tests__/ReactMount-test.js b/src/renderers/dom/client/__tests__/ReactMount-test.js
index bc7df11b775c..e7c20f80acac 100644
--- a/src/renderers/dom/client/__tests__/ReactMount-test.js
+++ b/src/renderers/dom/client/__tests__/ReactMount-test.js
@@ -20,7 +20,7 @@ describe('ReactMount', function() {
   var WebComponents = WebComponents;
 
   try {
-    if (WebComponents === undefined && jest !== undefined) {
+    if (WebComponents === undefined && typeof jest !== 'undefined') {
       WebComponents = require('WebComponents');
     }
   } catch(e) {
diff --git a/src/shared/vendor/third_party/webcomponents.js b/src/shared/vendor/third_party/webcomponents.js
index d114073e2d85..75431842f810 100755
--- a/src/shared/vendor/third_party/webcomponents.js
+++ b/src/shared/vendor/third_party/webcomponents.js
@@ -6374,4 +6374,6 @@ CustomElements.addModule(function(scope) {
   window.Platform = scope;
 })(window.WebComponents);
 
-module.exports = window.WebComponents;
+if (typeof exports !== 'undefined') {
+  module.exports = window.WebComponents;
+}