From 2d70aa14c3d6b1fb25bbb54f386f9db4cafa10d5 Mon Sep 17 00:00:00 2001
From: umair <umair.hussain@ably.com>
Date: Tue, 23 Dec 2025 13:01:38 +0000
Subject: [PATCH] Updates chat swift getting started guide to use more
 performant lookup

---
 src/pages/docs/chat/getting-started/swift.mdx | 75 ++++++++++++-------
 1 file changed, 47 insertions(+), 28 deletions(-)

diff --git a/src/pages/docs/chat/getting-started/swift.mdx b/src/pages/docs/chat/getting-started/swift.mdx
index 1725519f8e..cceb076689 100644
--- a/src/pages/docs/chat/getting-started/swift.mdx
+++ b/src/pages/docs/chat/getting-started/swift.mdx
@@ -329,11 +329,11 @@ struct ContentView: View {
                     }
                     messages.append(event.message)
                 case .updated:
-                    if let index = messages.firstIndex(where: { $0.id == event.message.id }) {
+                    if let index = messages.firstIndex(where: { $0.serial == event.message.serial }) {
                         messages[index] = event.message
                     }
                 case .deleted:
-                    if let index = messages.firstIndex(where: { $0.id == event.message.id }) {
+                    if let index = messages.firstIndex(where: { $0.serial == event.message.serial }) {
                         messages[index] = event.message
                     }
                 }
@@ -546,42 +546,61 @@ When you tap the "Edit" button next to a message, you can modify the text and it
 
 Ably Chat enables you to retrieve previously sent messages in a room. This is useful for providing conversational context when a user first joins a room, or when they subsequently rejoin it later on. The message subscription provides `historyBeforeSubscribe()` to enable this functionality. This method returns a paginated response, which can be queried further to retrieve the next set of messages.
 
-Update the `setupMessages` function in your `ContentView.swift` to retrieve previous messages:
+Add a new state variable `messageSerials` and update the `setupMessages` function in your `ContentView.swift` to retrieve previous messages:
 
 <Code>
 ```swift
-private func setupMessages(room: Room) {
-    let subscription = room.messages.subscribe { event in
-        withAnimation {
-            switch event.type {
-            case .created:
-                // Only add if not already in the list
-                if !messages.contains(where: { $0.id == event.message.id }) {
-                    messages.append(event.message)
-                }
-            case .updated:
-                if let index = messages.firstIndex(where: { $0.id == event.message.id }) {
-                    messages[index] = event.message
-                }
-            case .deleted:
-                if let index = messages.firstIndex(where: { $0.id == event.message.id }) {
-                    messages[index] = event.message
+struct ContentView: View {
+    private let roomName = "my-first-room"
+
+    @State private var chatClient: ChatClient
+    @State private var connectionStatus = ""
+    @State private var roomStatus = ""
+    @State private var room: Room?
+    @State private var messages: [Message] = []
+    @State private var messageSerials: Set<String> = []
+    @State private var newMessage = ""
+    @State private var editingMessage: Message?
+
+    // ... initialization code remains the same ...
+
+    private func setupMessages(room: Room) {
+        let subscription = room.messages.subscribe { event in
+            withAnimation {
+                switch event.type {
+                case .created:
+                    // Only add if not already in the list
+                    if !messageSerials.contains(event.message.serial) {
+                        messages.append(event.message)
+                        messageSerials.insert(event.message.serial)
+                    }
+                case .updated:
+                    if let index = messages.firstIndex(where: { $0.serial == event.message.serial }) {
+                        messages[index] = event.message
+                    }
+                case .deleted:
+                    if let index = messages.firstIndex(where: { $0.serial == event.message.serial }) {
+                        messages[index] = event.message
+                    }
                 }
             }
         }
-    }
 
-    // Get previous messages after subscribing
-    Task {
-        do {
-            let previousMessages = try await subscription.historyBeforeSubscribe(.init())
-            await MainActor.run {
-                messages.append(contentsOf: previousMessages.items)
+        // Get previous messages after subscribing
+        Task {
+            do {
+                let previousMessages = try await subscription.historyBeforeSubscribe(.init())
+                await MainActor.run {
+                    messages.append(contentsOf: previousMessages.items)
+                    messageSerials.formUnion(previousMessages.items.map(\.serial))
+                }
+            } catch {
+                print("Failed to get previous messages: \(error)")
             }
-        } catch {
-            print("Failed to get previous messages: \(error)")
         }
     }
+
+    // ... rest of the functions remain the same ...
 }
 ```
 </Code>