Dynamic Filter Suggestions

When you apply a filter on the Photos page, all other filter panels dynamically update to show only values that exist in the current result set. Every visible option is guaranteed to return results.

How it works

Select any filter value and the other panels narrow immediately:

1. Select Germany in Location -- People, Camera, Tags, Rating, and Media Type panels update to show only values present in German photos
2. Then select Canon in Camera -- the remaining panels narrow further to show only values for Canon photos taken in Germany
3. Every combination is valid -- you can never select a filter that produces zero results

This is called faceted search -- the same pattern used by Amazon, eBay, and other search-heavy applications.

What updates

Filter	Updates when other filters change?	Notes
People	Yes	Only people appearing in the filtered photos
Location	Yes (countries)	Cities update when you expand a country
Camera	Yes (makes)	Models update when you expand a make
Tags	Yes	Only tags assigned to filtered photos
Rating	Yes	Stars not present in the result set are hidden
Media Type	Yes	Photo/Video buttons hidden when no assets of that type
Timeline	Drives filtering	Selecting a year/month narrows all other panels
Favorites	Not dynamic	Simple toggle, always visible

Orphaned selections

If you select a value and then apply another filter that removes it from the available options, the selected value stays visible but appears dimmed. This lets you see why your result set might be empty and undo the selection with one click.

Debouncing

Filter changes are debounced to avoid excessive server requests:

• Discrete selections (clicking a person, country, tag): 50ms debounce to batch rapid clicks
• Temporal changes (selecting a year or month): 200ms debounce
• Clearing all filters: instant (0ms)

Previous in-flight requests are automatically cancelled when a new filter change occurs.

Architecture

A single API endpoint (GET /search/suggestions/filters) returns all suggestion categories in one round trip. The server runs 6 parallel queries -- one per category -- each applying all active filters except its own category. This exclusion is what makes it faceted: selecting Germany still shows all countries that match the other filters, not just Germany.

Server flow

Client: GET /search/suggestions/filters?country=Germany&withSharedSpaces=true

Server:
  1. Resolve user IDs (own + partners)
  2. Resolve shared space IDs (if withSharedSpaces)
  3. Run 6 queries in parallel:
     - Countries: all filters EXCEPT country/city
     - Camera makes: all filters EXCEPT make/model
     - Tags: all filters EXCEPT tagIds
     - People: all filters EXCEPT personIds
     - Ratings: all filters EXCEPT rating
     - Media types: all filters EXCEPT mediaType
  4. Return unified response

Client flow

FilterPanel:
  1. User changes a filter (e.g., clicks a country)
  2. Debounce (50ms for discrete, 200ms for temporal)
  3. Call suggestionsProvider(currentFilterState)
  4. Receive response with narrowed suggestions
  5. Update all filter panels
  6. Orphaned selections shown dimmed

Shared query helper

All 6 extraction queries share a common buildFilteredAssetIds helper that applies user/space scoping, temporal bounds, exif filters, person filters (via EXISTS), tag filters (via EXISTS), media type, and favorites. Each extraction method passes its own filter through without() to exclude its category before building the query.

Supported pages

Page	Dynamic suggestions?	Notes
Photos	Yes	Full cross-filter scoping
Map	Not yet	Uses individual providers (temporal scoping)
Spaces	Not yet	Uses individual providers (temporal scoping)

Map and Spaces pages can adopt the unified endpoint in the future with minimal changes -- the suggestionsProvider interface is generic and the endpoint supports spaceId scoping.