# Quality Checklist: Performance Phase 3 — Frontend Rendering

**Change**: 260327-cnav-perf-frontend-rendering
**Generated**: 2026-03-27
**Spec**: `spec.md`

## Functional Completeness

- [x] CHK-001 SSE diffing: `prevDataRef` stores previous `e.data` string and comparison skips `setSessions()` when unchanged
- [x] CHK-002 startTransition: `setSessions()` wrapped in `startTransition()`; `markConnected()` called outside transition
- [x] CHK-003 useChromeState: exported from `chrome-context.tsx`, returns `ChromeState`, throws outside `ChromeProvider`
- [x] CHK-004 Consumer migration: `app.tsx` and `top-bar.tsx` use `useChromeState()` for state-only reads
- [x] CHK-005 Palette groups: 7 independent useMemo groups composed into final `paletteActions`
- [x] CHK-006 Write batching: text buffer (string concatenation) and binary buffer (Uint8Array array) with rAF flush
- [x] CHK-007 rAF cleanup: `cancelAnimationFrame()` on WebSocket close and effect cleanup

## Behavioral Correctness

- [x] CHK-008 SSE connection liveness: `markConnected()` still called on every SSE event (both changed and unchanged)
- [x] CHK-009 Palette action order preserved: session → window → view → theme → config → server → terminal
- [x] CHK-010 Terminal reset: `needsReset` flag checked in onmessage (before buffering), not deferred to flush
- [x] CHK-011 Buffered data flushed on WebSocket close (no lost terminal output)

## Scenario Coverage

- [x] CHK-012 First SSE event triggers setSessions (empty string never matches valid JSON)
- [x] CHK-013 Unchanged SSE data skips setSessions (string equality)
- [x] CHK-014 Mixed text/binary WebSocket messages batched correctly (text concatenated, binary kept as chunks)
- [x] CHK-015 useChrome() backward compatibility — still returns ChromeState & ChromeDispatch

## Edge Cases & Error Handling

- [x] CHK-016 Malformed SSE event: try/catch still skips bad events without crashing
- [x] CHK-017 Terminal flush during teardown guarded against disposed terminal (try/catch)

## Code Quality

- [x] CHK-018 Pattern consistency: new hooks follow existing hook pattern (context check + throw)
- [x] CHK-019 No unnecessary duplication: useChromeState reuses ChromeStateContext (no new context)
- [x] CHK-020 No polling from client: SSE diff optimization doesn't introduce any polling
- [x] CHK-021 Type narrowing: no `as` casts introduced

## Notes

- Check items as you review: `- [x]`
- All items must pass before `/fab-continue` (hydrate)
- If an item is not applicable, mark checked and prefix with **N/A**: `- [x] CHK-008 **N/A**: {reason}`
