diff --git a/utils/files/readFile.js b/utils/files/readFile.js
index 631d6dc50..1fbb6aa00 100644
--- a/utils/files/readFile.js
+++ b/utils/files/readFile.js
@@ -16,7 +16,7 @@ const isNode = typeof window === 'undefined'
  */
 function readFile(file) {
   return new Promise((resolve, reject) => {
-    if (fs) {
+    if (isNode) {
       testFile(file, function(issue) {
         if (issue) {
           process.nextTick(function() {