fix: only collect height when visible

Author: zombieJ

examples/basic.tsx

@@ -50,6 +50,14 @@ const Demo = () => {
   const [type, setType] = React.useState('dom');
   const listRef = React.useRef<ListRef>(null);
 
+  React.useEffect(() => {
+    if (visible) {
+      listRef.current.scrollTo({
+        index: 50,
+      });
+    }
+  }, [visible]);
+
   return (
     <React.StrictMode>
       <div>

src/hooks/useHeights.tsx

@@ -37,7 +37,7 @@ export default function useHeights<T>(
 
   function collectHeight() {
     instanceRef.current.forEach((element, key) => {
-      if (element) {
+      if (element && element.offsetParent) {
         const htmlElement = findDOMNode<HTMLElement>(element);
         heightsRef.current.set(key, htmlElement.offsetHeight);
       }