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structuredClone loses ArrayBuffer and typed-array data #58218
Description
Description
The React Native structuredClone polyfill treats ArrayBuffer, DataView, and every typed array as arbitrary objects, returning plain objects that lose their internal bytes, view type, offsets, lengths, and shared backing-buffer relationships.
Expected behavior
ArrayBuffers should be copied through the intrinsic operation; DataView and all supported typed-array kinds should be reconstructed with their original offset/length and should share the same cloned backing buffer when cloned together. User-shadowed slice or constructor properties must not be invoked. Transfer support is outside this issue.
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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Missing reproducer: We could not detect a reproducible example in your issue report. Reproducers are mandatory and we can accept only one of those as a valid reproducer:
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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.
OskarEichler commentedon Oct 2, 2026
Added the requested runnable RNTester Playground in #58806. Open Playground and press Run reproducers; the result for #58218 is labeled separately.
Verified using the native Hermes/Fabric Fantom runner on main
cd2de187e8878119896159371225acbb9dfa5d9c. Ordinary ArrayBuffer/view aliasing now passes. The remaining shadowed-slice case fails withError: user slice ran.This is a constructed example based on the source audit, not a claimed production incident. The PR includes the exact native verification driver and results.