⚡ Bolt: [performance improvement] Defer expensive analysis during fake text streaming

[aloewright]

💡 What: We introduced useDeferredValue for the visibleOutput state in playground-view.tsx. This deferred value is now passed to the expensive synchronous computation analyzeText instead of the raw rapidly-updating stream state.

🎯 Why: During fake text streaming (which happens at ~24ms intervals), performing expensive computations (like analyzeText and scoreDeterministic) on every single frame updates blocks the main UI thread. This causes severe jank and input latency when the playground is simulating output.

📊 Impact: Reduces main thread blocking dramatically by allowing React to prioritize the rapid text-streaming UI updates and calculate the rubric snapshot only when there's idle time. The simulated output feels instantaneous without lagging.

🔬 Measurement: Run the Playground simulation and use Chrome Performance tools to trace rendering tasks. The long tasks block during output generation will be significantly reduced or eliminated.

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PR created automatically by Jules for task 16053177143148873668 started by @aloewright

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 21064a16-80b8-4d1d-92a6-399aa4828c8e

📥 Commits

Reviewing files that changed from the base of the PR and between bab8f67 and 4c02d0f.

📒 Files selected for processing (2)

• .jules/bolt.md
• apps/quill/client/components/playground-view.tsx

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch bolt/defer-playground-analysis-16053177143148873668

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Status	Name	Latest Commit	Updated (UTC)
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[gemini-code-assist]

Code Review

This pull request optimizes the UI performance during text streaming by utilizing React's useDeferredValue for the expensive analyzeText computation in the PlaygroundView component. A corresponding entry was also added to the project's learning log. Feedback suggests that for very large text inputs, the synchronous nature of the analysis might still cause performance issues, and recommends adding a visual indicator to signal when the analysis is lagging behind the current output.

[gemini-code-assist]

While useDeferredValue correctly mitigates UI blocking during streaming, the analyzeText function remains a synchronous, potentially expensive operation. If the text becomes very large, even a deferred render could cause a noticeable hitch when it eventually executes on the main thread. Consider providing a visual cue (e.g., reduced opacity) for the rubric section when the analysis is lagging behind the visible output.