diff --git a/src/jsutils/instanceOf.js b/src/jsutils/instanceOf.js
index e944809396..ec50c981e1 100644
--- a/src/jsutils/instanceOf.js
+++ b/src/jsutils/instanceOf.js
@@ -11,7 +11,8 @@ declare function instanceOf(
 
 // See: https://expressjs.com/en/advanced/best-practice-performance.html#set-node_env-to-production
 // See: https://webpack.js.org/guides/production/
-export default process.env.NODE_ENV === 'production'
+export default typeof process === 'undefined' ||
+process.env.NODE_ENV === 'production'
   ? /* istanbul ignore next (See: https://github.com/graphql/graphql-js/issues/2317) */
     // eslint-disable-next-line no-shadow
     function instanceOf(value: mixed, constructor: mixed) {