feat(clerk-js): Reuse SignIn/SignUp instances

[dstaley]

Description

This PR updates the Client JSON parsing logic to reuse existing SignIn and SignUp instances when the incoming IDs match the current instance. This results in a stable referential identity for client.signIn and client.signUp when possible. Previously, we were creating new instances of SignIn/SignUp on every request: one from the mutation HTTP request response, and another from the client piggybacking response. This caused two update events to be emitted, each with different instances of the class.

Checklist

• pnpm test runs as expected.
• pnpm build runs as expected.
• (If applicable) JSDoc comments have been added or updated for any package exports
• (If applicable) Documentation has been updated

Type of change

• 🐛 Bug fix
• 🌟 New feature
• 🔨 Breaking change
• 📖 Refactoring / dependency upgrade / documentation
• other:

Summary by CodeRabbit

• Improvements
  • Session instances (SignIn and SignUp) are now preserved and updated when receiving data with matching identifiers, rather than being replaced.

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Project	Deployment	Actions	Updated (UTC)
clerk-js-sandbox	Ready	Preview, Comment	Feb 9, 2026 3:58pm

[changeset-bot]

🦋 Changeset detected

Latest commit: 134f781

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@clerk/clerk-js	Minor
@clerk/chrome-extension	Patch
@clerk/expo	Patch

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commit: 134f781

[coderabbitai]

📝 Walkthrough

Walkthrough

This change modifies how the Client class processes SignIn and SignUp instances when handling JSON responses. Previously, new SignIn and SignUp objects were unconditionally created during fromJSON. Now, the logic checks if incoming data has matching IDs to existing instances. If IDs match, existing instances are updated via the new __internal_updateFromJSON method; if IDs differ, new instances are created. The __internal_updateFromJSON method is added to both SignIn and SignUp classes as an internal update path. Tests verify both behaviors: instance reuse when IDs match and replacement when IDs differ.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the main change: reusing SignIn/SignUp instances instead of recreating them, which is the primary focus of the changeset.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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[jacekradko]

Looks good!