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structuredClone coerces boxed primitives and flips false Boolean #58226
Description
Description
The React Native structuredClone polyfill reconstructs Number, String, Boolean, and Date wrappers by passing the source object to a constructor. Number/String cloning invokes user coercion hooks, and new Boolean(new Boolean(false)) uses object truthiness and silently changes the internal value to true.
Expected behavior
Cloning should read each wrapper's internal primitive through the built-in valueOf intrinsic, create a distinct wrapper with the same value, and never execute user coercion. 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
Warning
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 #58226 is labeled separately.
Verified using the native Hermes/Fabric Fantom runner on main
cd2de187e8878119896159371225acbb9dfa5d9c. The boxed Boolean(false) case still fails.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.