| name | feed-patterns |
| description | Feed composition and data-access layer patterns in Amethyst. Use when adding or modifying a feed (home, profile, hashtag, bookmarks, notifications, DMs, communities), working with the shared `FeedFilter` / `AdditiveFeedFilter` / `ChangesFlowFilter` / `FeedContentState` in `commons/.../ui/feeds/`, the Android-only `AdditiveComplexFeedFilter` / `FilterByListParams` in `amethyst/.../ui/dal/`, or extending the `FeedViewModel` family in `commons/.../viewmodels/`. Covers how feeds scan `LocalCache`, react to changes, apply ordering, and render through Compose. |
Feed Patterns
Amethyst's "feed" abstraction is: a FeedFilter that decides which notes belong in a list, plus a FeedViewModel that exposes the current state reactively to the UI. Every scrollable list — home, profile, hashtag, bookmarks, notifications, DMs — is a variant of this.
When to Use This Skill
- Adding a new screen that shows a list of notes.
- Modifying an existing feed's filtering / ordering / inclusion rules.
- Investigating why a feed doesn't update after a mute/follow/bookmark change.
- Deciding whether to extend a ViewModel or write a new filter.
- Understanding the Android ⇄ Desktop sharing boundary for feeds.
Architecture
┌─────────────────────────────────────────────────────────────┐
│ commons/.../viewmodels/ (shared, KMP) │
│ FeedViewModel ◄── ListChangeFeedViewModel │
│ ◄── ChatroomFeedViewModel │
│ ◄── MarmotGroupFeedViewModel │
│ │
│ │
│ commons/.../ui/feeds/ (shared, KMP) │
│ IFeedFilter / FeedFilter<T> (abstract base) │
│ IAdditiveFeedFilter / AdditiveFeedFilter<T> │
│ ChangesFlowFilter │
│ FeedContentState, FeedState — the flow the UI collects │
└─────────────────────────────────────────────────────────────┘
▲
│ uses
│
┌─────────────────────────────────────────────────────────────┐
│ amethyst/.../ui/dal/ (Android-only additions) │
│ AdditiveComplexFeedFilter<T, U> │
│ FilterByListParams │
│ DefaultFeedOrder (Note/Event/Card comparators) │
│ (FeedFilters.kt & ChangesFlowFilter.kt here are just │
│ back-compat typealiases re-exporting commons) │
│ │
│ Concrete feeds: HomeNewThreadFeedFilter, │
│ HashtagFeedFilter, NotificationFeedFilter, … live in │
│ feature folders under ui/screen/loggedIn/*/dal/ │
└─────────────────────────────────────────────────────────────┘
▲
│ reads
│
┌─────────────────────────────────────────────────────────────┐
│ model/LocalCache.kt + account.<feature>.flow │
└─────────────────────────────────────────────────────────────┘
