Merge pull request #827 from planetary-social/limit-notifications-view

Limit NotificationsView to 100 results.

CHANGELOG.md

@@ -7,7 +7,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
-
+
+- Optimized loading of the Notifications tab
 - Updated suggested users for discovery tab.
 - Show the profile view when a search matches a valid User ID (npub).
 - Added tabs to Profiles to filter posts.

Nos/Models/CoreData/Event+CoreDataClass.swift

@@ -59,18 +59,6 @@ public enum EventKind: Int64, CaseIterable, Hashable {
     case notificationServiceRegistration = 6666
 }
 
-extension FetchedResults where Element == Event {
-    var unmuted: [Event] {
-        filter {
-            if let author = $0.author {
-                let notDeleted = $0.deletedOn.count == 0
-                return !author.muted && notDeleted
-            }
-            return false
-        }
-    }
-}
-
 // swiftlint:disable type_body_length
 @objc(Event)
 @Observable
@@ -298,9 +286,22 @@ public class Event: NosManagedObject {
         )
     }
 
-    @nonobjc public class func all(notifying user: Author, since: Date? = nil) -> NSFetchRequest<Event> {
+    /// A request for all events that the given user should receive a notification for.
+    /// - Parameters:
+    ///   - user: the author you want to view notifications for.
+    ///   - since: a date that will be used as a lower bound for the request.
+    ///   - limit: a max number of events to fetch.
+    /// - Returns: A fetch request for the events described.
+    @nonobjc public class func all(
+        notifying user: Author, 
+        since: Date? = nil, 
+        limit: Int? = nil
+    ) -> NSFetchRequest<Event> {
         let fetchRequest = NSFetchRequest<Event>(entityName: "Event")
         fetchRequest.sortDescriptors = [NSSortDescriptor(keyPath: \Event.createdAt, ascending: false)]
+        if let limit {
+            fetchRequest.fetchLimit = limit
+        }
 
         let mentionsPredicate = allMentionsPredicate(for: user)
         let repliesPredicate = allRepliesPredicate(for: user)

Nos/Views/NotificationsView.swift

@@ -21,20 +21,22 @@ struct NotificationsView: View {
     @Dependency(\.pushNotificationService) private var pushNotificationService
     @Dependency(\.persistenceController) private var persistenceController
 
-    private var eventRequest: FetchRequest<Event> = FetchRequest(fetchRequest: Event.emptyRequest())
-    private var events: FetchedResults<Event> { eventRequest.wrappedValue }
+    @FetchRequest private var events: FetchedResults<Event>
     @State private var relaySubscriptions = SubscriptionCancellables()
     @State private var isVisible = false
 
     @State private var concecutiveTapsCancellable: AnyCancellable?
 
     // Probably the logged in user should be in the @Environment eventually
     private var user: Author?
+    private let maxNotificationsToShow = 100
 
     init(user: Author?) {
         self.user = user
         if let user {
-            eventRequest = FetchRequest(fetchRequest: Event.all(notifying: user))
+            _events = FetchRequest(fetchRequest: Event.all(notifying: user, limit: maxNotificationsToShow))
+        } else {
+            _events = FetchRequest(fetchRequest: Event.emptyRequest())
         }
     }    
 
@@ -74,8 +76,11 @@ struct NotificationsView: View {
         NavigationStack(path: $router.notificationsPath) {
             ScrollView(.vertical) {
                 LazyVStack {
-                    ForEach(events.unmuted) { event in
-                        if let user {
+                    /// The fetch request for events has a `fetchLimit` set but it doesn't work, so we limit the
+                    /// number of views displayed here and that appears to prevent @FetchRequest from loading all the
+                    /// records into memory.
+                    ForEach(0..<maxNotificationsToShow, id: \.self) { index in
+                        if let event = events[safe: index], let user {
                             NotificationCard(viewModel: NotificationViewModel(note: event, user: user))
                                 .padding(.horizontal, 15)
                                 .padding(.bottom, 10)