---
id: S02
parent: M012
milestone: M012
provides:
  - Sort query param on search, subtopic, topic, and techniques endpoints
  - SortDropdown component and useSortPreference hook for reuse
requires:
  - slice: S01
    provides: Multi-field composite search endpoints
affects:
  []
key_files:
  - backend/routers/search.py
  - backend/routers/topics.py
  - backend/routers/techniques.py
  - backend/search_service.py
  - frontend/src/components/SortDropdown.tsx
  - frontend/src/hooks/useSortPreference.ts
  - frontend/src/pages/SearchResults.tsx
  - frontend/src/pages/SubTopicPage.tsx
  - frontend/src/pages/CreatorDetail.tsx
  - frontend/src/api/public-client.ts
  - frontend/src/App.css
key_decisions:
  - Sort applied in Python for search results (mixed Qdrant + keyword sources), SQL ORDER BY for single-source endpoints
  - Shared sessionStorage key across all pages for unified sort preference
  - Page-specific option lists with context-appropriate defaults (relevance for search, alpha for subtopic, newest for creator)
patterns_established:
  - Reusable SortDropdown + useSortPreference hook pattern for adding sort controls to any list page
  - sessionStorage for session-scoped UI preferences that don't need server persistence
observability_surfaces:
  - none
drill_down_paths:
  - .gsd/milestones/M012/slices/S02/tasks/T01-SUMMARY.md
  - .gsd/milestones/M012/slices/S02/tasks/T02-SUMMARY.md
duration: ""
verification_result: passed
completed_at: 2026-04-01T06:35:19.120Z
blocker_discovered: false
---

# S02: Sort Controls on All List Views

**Added sort dropdown to SearchResults, SubTopicPage, and CreatorDetail with backend sort params and session-persistent preference via sessionStorage.**

## What Happened

Two tasks delivered the full sort stack. T01 added a `sort` query parameter to four backend endpoints — search, subtopic, category topics, and techniques — supporting relevance/newest/oldest/alpha/creator options. Search results use Python-level sorting (mixed Qdrant + keyword sources), while single-source endpoints use SQL ORDER BY. Creator sort joins the Creator table. T02 built a reusable SortDropdown component and useSortPreference hook backed by sessionStorage. Integrated into three pages with context-appropriate option lists and defaults (relevance for search, alpha for subtopic, newest for creator). The sort param flows through public-client.ts to the API. Changing sort resets pagination. Deployed to ub01 and verified end-to-end: alphabetical sort on search returns A-Z titles, oldest sort on subtopic returns ascending dates, preference persists across navigation.

## Verification

Backend: curl verified search?sort=alpha returns alphabetically ordered titles, topics/sound-design/bass?sort=oldest returns ascending created_at dates, techniques?sort=creator returns creator-grouped results. Frontend: TypeScript compilation clean (npx tsc --noEmit), Vite build successful. Browser verification on ub01:8096 confirmed all three pages show sort dropdown, sort changes update results, sessionStorage persists preference across navigation.

## Requirements Advanced

None.

## Requirements Validated

None.

## New Requirements Surfaced

None.

## Requirements Invalidated or Re-scoped

None.

## Deviations

T01 added sort param to the category-level topic endpoint (get_topic_techniques) beyond the original plan, for frontend consistency.

## Known Limitations

None.

## Follow-ups

None.

## Files Created/Modified

- `backend/routers/search.py` — Added sort query param, passed to SearchService
- `backend/routers/topics.py` — Added sort param to subtopic and category topic endpoints with SQL ORDER BY
- `backend/routers/techniques.py` — Extended sort options with oldest/alpha/creator
- `backend/search_service.py` — Added _apply_sort for Python-level sorting of enriched results, added created_at to result dicts
- `frontend/src/components/SortDropdown.tsx` — New reusable sort dropdown component
- `frontend/src/hooks/useSortPreference.ts` — New hook for sessionStorage-backed sort preference
- `frontend/src/pages/SearchResults.tsx` — Integrated SortDropdown with search-specific options
- `frontend/src/pages/SubTopicPage.tsx` — Integrated SortDropdown with subtopic-specific options
- `frontend/src/pages/CreatorDetail.tsx` — Integrated SortDropdown with creator-specific options
- `frontend/src/api/public-client.ts` — Added sort param to searchApi and fetchSubTopicTechniques
- `frontend/src/App.css` — Dark-theme styles for sort dropdown with custom chevron and focus ring
