yellowjacket/.planning/phases/14-performance-optimization/14-02-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
14-performance-optimization	02	ui	navigation view-caching dom performance display-toggle		View caching navigation system — primary views created once and visibility-toggled viewCache Map with bounded 6-entry cache for primary views Ephemeral detail view lifecycle (artist-details, playlist-details, genre-details)	14-performance-optimization	added patterns View cache Map<string, HTMLElement> for DOM-persistent primary views display:none/display:'' toggle instead of innerHTML destruction Ephemeral detail views (remove + create) vs cached primary views	created modified frontend/index.ts	Primary views cached, detail views ephemeral — detail views depend on entity IDs that change per navigation Inline style.display toggle over CSS class — simpler, no specificity issues, direct JS control viewCache bounded at 6 entries (one per primary view) — negligible memory overhead	View caching: create once, toggle visibility, never destroy primary views Detail view lifecycle: hide primary view, remove old detail, create new detail	PERF-NAV-01 PERF-NAV-02	1min	2026-03-14

Phase 14 Plan 02: View Caching Navigation Summary

DOM-persistent view cache replacing innerHTML destruction — primary views created once and visibility-toggled for instant navigation

Performance

• Duration: 1 min
• Started: 2026-03-14T17:43:20Z
• Completed: 2026-03-14T17:44:52Z
• Tasks: 1
• Files modified: 1

Accomplishments

• Replaced innerHTML-based navigation with a view caching system using a Map<string, HTMLElement>
• Primary views (tracks, albums, artists, genres, playlists, settings) created once and kept in DOM
• Navigation toggles display:none / display:'' instead of destroying and recreating components
• Detail views (artist-details, playlist-details, genre-details) remain ephemeral with proper lifecycle (remove old, create new)
• Scroll positions naturally preserved since DOM is never destroyed
• No virtualizer reinit, no data refetch, no cover art image reload on navigation

Task Commits

Each task was committed atomically:

1. Task 1: Implement view caching navigation system - ad91043 (perf)

Files Created/Modified

• frontend/index.ts - Replaced switch/innerHTML navigation with VIEW_TAGS map, viewCache Map, display toggle, and ephemeral detail view lifecycle

Decisions Made

• Primary views cached, detail views ephemeral — Detail views (artist-details, playlist-details, genre-details) depend on entity IDs/names that change per navigation, so caching them would show stale content. Primary views are stateless navigation targets that benefit from persistence.
• Inline style.display toggle — Using element.style.display = 'none' / element.style.display = '' rather than CSS classes avoids specificity issues and gives direct control. The empty string restores the element's natural display value from CSS (.main-panel > * { height: 100% }).
• viewCache bounded at 6 entries — One entry per primary view tag in VIEW_TAGS. Memory overhead is negligible since the data each view holds is already in store caches regardless.

Deviations from Plan

None - plan executed exactly as written.

Issues Encountered

None

User Setup Required

None - no external service configuration required.

Next Phase Readiness

• View caching complete — ready for remaining Phase 14 plans (14-01 CSS containment, 14-03 store optimizations, 14-04 rendering optimizations)
• Existing scroll save/restore logic in components preserved as fallback for data invalidation scenarios

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Self-Check: PASSED

• ✅ frontend/index.ts exists
• ✅ Commit ad91043 exists

Phase: 14-performance-optimization Completed: 2026-03-14