yellowjacket/.planning/phases/08-frontend-performance-ux/08-03-SUMMARY.md

phase, plan, subsystem, tags, requires, provides, affects, tech-stack, key-files, key-decisions, patterns-established, requirements-completed, duration, completed

phase	plan	subsystem	tags	requires	provides	affects	tech-stack	key-files	key-decisions	patterns-established	requirements-completed	duration	completed
08-frontend-performance-ux	03	frontend	lit classMap performance render-optimization directives	phase provides 08-frontend-performance-ux repeat() directive migration on all virtualizer instances	classMap directive for conditional CSS classes in track-list renderTrackRow and queue-panel renderTrackItem Search highlight short-circuit when search term is empty Hoisted search term lookup outside per-column iteration loop	08-frontend-performance-ux	added patterns classMap directive for conditional CSS classes in render hot paths	created modified frontend/src/components/track-list/track-list.ts frontend/src/components/queue-panel/queue-panel.ts	classMap object literal per-call is acceptable — classMap internally diffs and only updates changed classes Hoisted searchCtrl.term outside cols.map to avoid repeated property access per column	Render hot path pattern: use classMap directive instead of array filter/join for conditional CSS classes	PERF-05 UX-02	2min	2026-03-05

Phase 8 Plan 03: renderTrackRow Optimization Summary

Replaced array filter/join class construction with classMap directive in track-list and queue-panel render hot paths, eliminating per-row array allocations during scrolling

Performance

• Duration: 2 min
• Started: 2026-03-05T04:19:55Z
• Completed: 2026-03-05T04:22:19Z
• Tasks: 2
• Files modified: 2

Accomplishments

• All conditional CSS class construction in renderTrackRow (track-row, fav-icon, cell) converted from array filter/join to classMap directive
• Queue-panel renderTrackItem class construction (track-item, active, selected, drop-before, drop-after) converted to classMap
• Search term property lookup hoisted outside per-column loop to avoid repeated access
• Search highlighting already short-circuits when term is empty — no additional optimization needed

Task Commits

Each task was committed atomically:

1. Task 1: Replace class string construction with classMap directive in renderTrackRow - ad21027 (perf)
2. Task 2: Optimize column value computation and apply classMap to queue-panel renderTrackItem - 62f41c2 (perf)

Files Created/Modified

• frontend/src/components/track-list/track-list.ts - classMap for track-row, fav-icon, and cell classes; hoisted search term lookup
• frontend/src/components/queue-panel/queue-panel.ts - classMap for track-item with active, selected, drop-before, drop-after states

Decisions Made

• classMap object literal allocation per-call is acceptable since classMap internally diffs previous values and only applies DOM changes for actually changed classes — net benefit over string concatenation in Lit's update cycle
• Hoisted searchCtrl.term outside the cols.map loop — avoids redundant property access per column per row

Deviations from Plan

None - plan executed exactly as written.

Issues Encountered

None

User Setup Required

None - no external service configuration required.

Next Phase Readiness

• All render hot path optimizations complete for track-list and queue-panel
• Ready for Plan 04 (final phase 8 plan)

Self-Check: PASSED

All key files exist on disk. All task commits verified in git history.

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Phase: 08-frontend-performance-ux Completed: 2026-03-05