From 1850a985b50e46cc06ebab8387e594270d7baad8 Mon Sep 17 00:00:00 2001
From: Classic298 <27028174+Classic298@users.noreply.github.com>
Date: Fri, 6 Mar 2026 21:02:57 +0100
Subject: [PATCH] =?UTF-8?q?perf:=20replace=20O(n=C2=B2)=20unshift=20with?=
 =?UTF-8?q?=20O(n)=20push+reverse=20in=20buildMessages=20(#22280)?=
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Array.unshift() is O(n) per call because it shifts all existing
elements. In a loop building an n-element array, this makes the
total cost O(n²). Replace with push() + reverse() which is O(n)
total. Produces the identical message ordering.
---
 src/lib/components/chat/Messages.svelte | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lib/components/chat/Messages.svelte b/src/lib/components/chat/Messages.svelte
index dbd8daa16e..e8ada5c57c 100644
--- a/src/lib/components/chat/Messages.svelte
+++ b/src/lib/components/chat/Messages.svelte
@@ -90,11 +90,11 @@
 			}
 			visitedMessageIds.add(message.id);
 
-			_messages.unshift(message);
+			_messages.push(message);
 			message = message.parentId !== null ? history.messages[message.parentId] : null;
 		}
 
-		messages = _messages;
+		messages = _messages.reverse();
 	};
 
 	// Throttle message list rebuilds to once per animation frame during streaming.