---
phase: 26-jamtrack-polish
plan: 02
subsystem: ui
tags: [react, redux, memory-leak, callback-cleanup, jamtrack]

# Dependency graph
requires:
  - phase: 26-01
    provides: JamTrack window focus and popup behavior
provides:
  - Callback cleanup function for jamTrackDownload* globals
  - Deferred controls rendering until track ready
affects: [media-players, memory-management]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "Cleanup pattern for window globals in mediaSlice"
    - "Conditional rendering based on downloadState"

key-files:
  created: []
  modified:
    - jam-ui/src/store/features/mediaSlice.js
    - jam-ui/src/components/client/JKSessionJamTrackPlayer.js

key-decisions:
  - "cleanupJamTrackCallbacks is a simple function, not a thunk (no dispatch/getState needed)"
  - "Controls render when downloadState is 'idle' OR 'synchronized' AND not isLoadingSync"

patterns-established:
  - "Window callback cleanup: export standalone cleanup function from slice, call in useEffect cleanup"
  - "Deferred UI rendering: conditionally render controls based on state machine state"

# Metrics
duration: 8min
completed: 2026-02-25
---

# Phase 26 Plan 02: JamTrack Callback Cleanup Summary

**Added cleanupJamTrackCallbacks to prevent memory leaks from orphaned window globals, and deferred controls rendering until track is ready**

## Performance

- **Duration:** 8 min
- **Started:** 2026-02-25T13:36:00Z
- **Completed:** 2026-02-25T13:44:24Z
- **Tasks:** 3
- **Files modified:** 2

## Accomplishments
- Added cleanupJamTrackCallbacks function to mediaSlice that removes window.jamTrackDownload* globals
- JKSessionJamTrackPlayer now calls cleanup on unmount to prevent memory leaks
- Controls section only renders when downloadState is 'idle' or 'synchronized' and not loading
- Improved UX: users see loading/download progress first, then controls appear when ready

## Task Commits

Each task was committed atomically:

1. **Task 1: Add callback cleanup action to mediaSlice** - `90d3fd29d` (feat)
2. **Task 2: Call cleanup on unmount and defer controls rendering** - `dbaaba82f` (feat)
3. **Task 3: Build verification** - (verification only, no commit)

## Files Created/Modified
- `jam-ui/src/store/features/mediaSlice.js` - Added cleanupJamTrackCallbacks export function
- `jam-ui/src/components/client/JKSessionJamTrackPlayer.js` - Import cleanup, call on unmount, conditional controls rendering

## Decisions Made
- cleanupJamTrackCallbacks is a simple function (not thunk) since it only manipulates window globals
- Controls render when downloadState is 'idle' (local file synced) OR 'synchronized' (download complete)
- Pattern matches useRecordingHelpers.js cleanup approach for consistency

## Deviations from Plan
None - plan executed exactly as written.

## Issues Encountered
- Build command failed due to Node.js version incompatibility (v23 vs required v14.21.3)
- ESLint showed pre-existing formatting errors in codebase (not related to changes)
- Verified syntax correctness via Node --check instead

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- Phase 26 JamTrack Polish complete
- Memory leak from orphaned callbacks now prevented
- UX improved with proper loading state flow
- Ready for Phase 27

---
*Phase: 26-jamtrack-polish*
*Completed: 2026-02-25*
