diff --git a/docs/src/main.js b/docs/src/main.js
index 9c58ff665..89ff3e6af 100644
--- a/docs/src/main.js
+++ b/docs/src/main.js
@@ -11,7 +11,7 @@ export default function (Vue, { head }) {
   head.htmlAttrs = { 'data-theme': 'dark' }
 
   // fix docsearch
-  if (!window.process) {
+  if (window && !window.process) {
     window.process = {
       env: {
         NODE_ENV: 'production',