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structuredClone shortens sparse arrays with trailing holes #58208
Description
Description
The React Native structuredClone polyfill initializes an array clone as [] and only assigns enumerable keys. If a sparse array's highest populated index precedes its declared length, the trailing holes are lost and the clone is silently shortened. For example, new Array(3) with only index 1 populated becomes length 2.
Expected behavior
The clone should preserve the source array's declared length and holes. Node's native structuredClone follows this behavior.
React Native Version
0.87.1 and current main
Affected Platforms
JavaScript runtime - All
Activity
react-native-bot commentedon Aug 30, 2026
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react-native-bot commentedon Sep 24, 2026
This issue is waiting for author's feedback since 24 days. Please provide the requested feedback or this will be closed in 7 days.
react-native-bot commentedon Oct 1, 2026
This issue was closed because the author hasn't provided the requested feedback after 7 days.
react-native-bot commentedon Oct 1, 2026
This issue was closed because it has been stalled for 7 days with no activity.