From 576ee9243890e612652886d46c464e86b4f1a6f4 Mon Sep 17 00:00:00 2001
From: Classic298 <27028174+Classic298@users.noreply.github.com>
Date: Fri, 6 Mar 2026 22:36:13 +0100
Subject: [PATCH] perf: rewrite createMessagesList from recursive to iterative
 (#22194)

Replace the recursive spread-based implementation with an iterative
push+reverse approach. The recursive version created a new array at
each level of recursion via spread, resulting in O(d^2) array copies
where d is the conversation depth. The iterative version walks from
the target message to the root, pushes each message, and reverses
once at the end for O(d) total work.

No behavioral change - same input produces the same output array.
---
 src/lib/utils/index.ts | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/lib/utils/index.ts b/src/lib/utils/index.ts
index 4a1cf2e91..18c5c6b67 100644
--- a/src/lib/utils/index.ts
+++ b/src/lib/utils/index.ts
@@ -1181,19 +1181,19 @@ export const getWeekday = () => {
 };
 
 export const createMessagesList = (history, messageId) => {
-	if (messageId === null) {
-		return [];
+	const list = [];
+	let currentId = messageId;
+
+	while (currentId !== null && currentId !== undefined) {
+		const message = history.messages[currentId];
+		if (message === undefined) {
+			break;
+		}
+		list.push(message);
+		currentId = message.parentId;
 	}
 
-	const message = history.messages[messageId];
-	if (message === undefined) {
-		return [];
-	}
-	if (message?.parentId) {
-		return [...createMessagesList(history, message.parentId), message];
-	} else {
-		return [message];
-	}
+	return list.reverse();
 };
 
 export const formatFileSize = (size) => {