VirtualizedList onViewableItemsChanged won't trigger if first item in…

… data evaluate to false #35280 (#35282)

Summary:
VirtualizedList onViewableItemsChanged won't trigger if first item in data evaluate to false #35280

Described in #35280

## Changelog

- [General] [Fixed] Fix VirtualizedList onViewableItemsChanged won't trigger if first item in data evaluate to false

Pull Request resolved: #35282

Test Plan:
this snack will be able to log `onViewableItemsChanged triggered` after the fix:
https://snack.expo.dev/tmQo_R_3Y

Reviewed By: jacdebug

Differential Revision: D41158485

Pulled By: NickGerleman

fbshipit-source-id: 47434890155abe009c2560b658adc4e067c31027

Libraries/Lists/VirtualizedList.js

@@ -1749,7 +1749,10 @@ export default class VirtualizedList extends StateSafePureComponent<
  'Tried to get frame for out of range index ' + index,
  );
  const item = getItem(data, index);
- const frame = item && this._frames[this._keyExtractor(item, index, props)];
+ const frame =
+ item != null
+ ? this._frames[this._keyExtractor(item, index, props)]
+ : undefined;
  if (!frame || frame.index !== index) {
  if (getItemLayout) {
  /* $FlowFixMe[prop-missing] (>=0.63.0 site=react_native_fb) This comment