structuredClone invokes custom Map and Set iterators
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Description
Description
The React Native structuredClone polyfill traverses Map and Set values with for...of. An own Symbol.iterator override is therefore executed and can change the cloned contents or abort cloning, even though structured cloning should read the built-in collection data from internal slots.
Expected behavior
Map and Set cloning should ignore user iterator overrides and clone their real built-in entries, matching native structuredClone.
React Native Version
0.87.1 and current main
Affected Platforms
JavaScript runtime - All
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start at the React Native structuredClone polyfill and inspect how Map and Set values are traversed. Reproduce the issue with own Symbol.iterator overrides and compare the result with native structuredClone. Done means cloning uses built-in entries, ignores those overrides, and preserves expected behavior on JavaScript runtimes.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript, react-native
- Domain
- mobile-dev
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Active
- Clarity
- Mostly clear
- Newbie friendliness
- 68/100