diff --git a/src/createGridComponent.js b/src/createGridComponent.js
index 72d5c525..7e8fc85e 100644
--- a/src/createGridComponent.js
+++ b/src/createGridComponent.js
@@ -132,7 +132,7 @@ const defaultItemKey = ({ columnIndex, data, rowIndex }) =>
 let devWarningsOverscanCount = null;
 let devWarningsTagName = null;
 if (process.env.NODE_ENV !== 'production') {
-  if (typeof window.WeakSet !== 'undefined') {
+  if (typeof window !== 'undefined' && typeof window.WeakSet !== 'undefined') {
     devWarningsOverscanCount = new WeakSet();
     devWarningsTagName = new WeakSet();
   }
diff --git a/src/createListComponent.js b/src/createListComponent.js
index ae45952d..eb41277c 100644
--- a/src/createListComponent.js
+++ b/src/createListComponent.js
@@ -112,7 +112,7 @@ const defaultItemKey = (index: number, data: any) => index;
 let devWarningsDirection = null;
 let devWarningsTagName = null;
 if (process.env.NODE_ENV !== 'production') {
-  if (typeof window.WeakSet !== 'undefined') {
+  if (typeof window !== 'undefined' && typeof window.WeakSet !== 'undefined') {
     devWarningsDirection = new WeakSet();
     devWarningsTagName = new WeakSet();
   }