structuredClone loses own __proto__ data properties

Description

The React Native structuredClone polyfill copies enumerable properties with ordinary assignment. For an own __proto__ data property on an object or array, assignment invokes the inherited prototype setter: the clone's prototype is replaced and no own property is created.

Expected behavior

__proto__ should be cloned as an ordinary own enumerable/writable/configurable data property with a deeply cloned value, while the clone keeps its normal Object or Array prototype. Native structuredClone follows this behavior.

React Native Version

0.87.1 and current main

Affected Platforms

JavaScript runtime - All

エントリーポイントは React Native の structuredClone polyfill です。まず、列挙可能な自所有の proto データプロパティを持つオブジェクトと配列で問題を再現します。clone が通常の Object または Array の prototype を保持し、native の structuredClone の動作に一致する、深く clone された自所有プロパティを持てば完了です。