fix(useSize): prevents accessing iframe's property when it's not… (#443)

fix(useSize): prevents accessing iframe's property when it's not defined
streamich · Jul 4, 2019 · 8f04e8f · 8f04e8f
2 parents cf68e36 + c9b5cdc
commit 8f04e8f
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/src/useSize.tsx b/src/useSize.tsx
@@ -45,7 +45,13 @@ const useSize = (
   };
 
   useEffect(() => {
-    const iframe: HTMLIFrameElement = ref.current!;
+    const iframe: HTMLIFrameElement = ref.current;
+
+    if(!iframe) {
+      // iframe will be undefined if component is already unmounted
+      return;
+    }
+
     if (iframe.contentWindow) {
       window = iframe.contentWindow!;
       onWindow(window);