feat(ui): Add support for localization nodes

[alexcarpenter]

Description

Add support for inline <bold> markup in localization values, rendered as <strong> elements. Translators can now write 'Agree to <bold>Terms</bold>' in a single key instead of splitting into prefix/bold/suffix fragments. Token values are substituted only into parsed text leaves, so user-controlled data can never become markup. Also hardens applyTokensToString to use Object.prototype.hasOwnProperty.call when filtering token names, preventing prototype-chain names like {{hasOwnProperty}} from crashing rendering.

in support for #8535

localization: {signIn: {start: {title: 'Sign in to <bold>{{applicationName}}</bold>',},},}

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:

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Project	Deployment	Actions	Updated (UTC)
clerk-js-sandbox	Ready	Preview, Comment	May 13, 2026 2:55pm

[changeset-bot]

🦋 Changeset detected

Latest commit: 4fe4353

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

This PR includes changesets to release 2 packages

Name	Type
@clerk/ui	Minor
@clerk/chrome-extension	Patch

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository YAML (base), Organization UI (inherited)

Review profile: CHILL

Plan: Pro

Run ID: 5d82b676-025f-4645-8608-3ed3f8dd51d7

📥 Commits

Reviewing files that changed from the base of the PR and between d19f13e and 4fe4353.

📒 Files selected for processing (1)

• .changeset/inline-bold-localization-markup.md

✅ Files skipped from review due to trivial changes (1)

• .changeset/inline-bold-localization-markup.md

---

📝 Walkthrough

Walkthrough

Adds parsing and rendering for inline markup (converted to React ), integrates node-based localized rendering via localizedNodeFromKey, makes t() return markup-stripped strings, tightens token matching to own properties, and includes extensive tests covering correctness, injection-resistance, malformed-input fallbacks, performance bounds, SSR determinism, and module-state isolation.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'feat(ui): Add support for localization nodes' accurately and specifically describes the main change: adding support for localization nodes with inline bold markup.
Description check	✅ Passed	The description clearly explains the purpose and scope of the changes: inline markup support in localization values, token substitution behavior, and security hardening of token filtering.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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commit: 4fe4353

[jacekradko]

@alexcarpenter are we planning on supporting <bold>Application Name</bold> being passed in as {{applicationName}} ?