From e5f31c2e14058228769158d2a1f654e3cecdb05a Mon Sep 17 00:00:00 2001
From: Algorithm5838 <108630393+Algorithm5838@users.noreply.github.com>
Date: Fri, 17 Apr 2026 08:22:06 +0300
Subject: [PATCH] perf: replace JSON.stringify equality with fast-deep-equal
 (#23370)

---
 package-lock.json                                           | 2 +-
 package.json                                                | 1 +
 .../components/chat/Messages/MultiResponseMessages.svelte   | 3 ++-
 src/lib/components/chat/Messages/ResponseMessage.svelte     | 3 ++-
 .../chat/Messages/ResponseMessage/StatusHistory.svelte      | 6 ++----
 src/lib/components/chat/Messages/UserMessage.svelte         | 3 ++-
 6 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 538792470e..e917faa608 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -54,6 +54,7 @@
 				"dayjs": "^1.11.10",
 				"dompurify": "^3.2.6",
 				"eventsource-parser": "^1.1.2",
+				"fast-deep-equal": "^3.1.3",
 				"file-saver": "^2.0.5",
 				"focus-trap": "^7.6.4",
 				"fuse.js": "^7.0.0",
@@ -8462,7 +8463,6 @@
 			"version": "3.1.3",
 			"resolved": "https://registry.npmjs.org/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz",
 			"integrity": "sha512-f3qQ9oQy9j2AhBe/H9VC91wLmKBCCU/gDOnKNAYG5hswO7BLKj09Hc5HYNz9cGI++xlpDCIgDaitVs03ATR84Q==",
-			"dev": true,
 			"license": "MIT"
 		},
 		"node_modules/fast-fifo": {
diff --git a/package.json b/package.json
index ab0cf78afc..204f35d51f 100644
--- a/package.json
+++ b/package.json
@@ -98,6 +98,7 @@
 		"dayjs": "^1.11.10",
 		"dompurify": "^3.2.6",
 		"eventsource-parser": "^1.1.2",
+		"fast-deep-equal": "^3.1.3",
 		"file-saver": "^2.0.5",
 		"focus-trap": "^7.6.4",
 		"fuse.js": "^7.0.0",
diff --git a/src/lib/components/chat/Messages/MultiResponseMessages.svelte b/src/lib/components/chat/Messages/MultiResponseMessages.svelte
index ae2be93ff2..a6d5a9b8a7 100644
--- a/src/lib/components/chat/Messages/MultiResponseMessages.svelte
+++ b/src/lib/components/chat/Messages/MultiResponseMessages.svelte
@@ -19,6 +19,7 @@
 	import localizedFormat from 'dayjs/plugin/localizedFormat';
 	import ProfileImage from './ProfileImage.svelte';
 	import { WEBUI_BASE_URL } from '$lib/constants';
+	import equal from 'fast-deep-equal';
 	const i18n = getContext('i18n');
 	dayjs.extend(localizedFormat);
 
@@ -66,7 +67,7 @@
 		if (source) {
 			if (message.content !== source.content || message.done !== source.done) {
 				message = structuredClone(source);
-			} else if (JSON.stringify(message) !== JSON.stringify(source)) {
+			} else if (!equal(message, source)) {
 				message = structuredClone(source);
 			}
 		}
diff --git a/src/lib/components/chat/Messages/ResponseMessage.svelte b/src/lib/components/chat/Messages/ResponseMessage.svelte
index 35e592d139..ebae97d95b 100644
--- a/src/lib/components/chat/Messages/ResponseMessage.svelte
+++ b/src/lib/components/chat/Messages/ResponseMessage.svelte
@@ -37,6 +37,7 @@
 		removeAllDetails
 	} from '$lib/utils';
 	import { WEBUI_API_BASE_URL, WEBUI_BASE_URL } from '$lib/constants';
+	import equal from 'fast-deep-equal';
 
 	import Name from './Name.svelte';
 	import ProfileImage from './ProfileImage.svelte';
@@ -127,7 +128,7 @@
 			// Avoids 2x O(n) JSON.stringify calls that are always true during streaming anyway
 			if (message.content !== source.content || message.done !== source.done) {
 				message = structuredClone(source);
-			} else if (JSON.stringify(message) !== JSON.stringify(source)) {
+			} else if (!equal(message, source)) {
 				// Slow path: full comparison for infrequent changes (sources, annotations, status, etc.)
 				message = structuredClone(source);
 			}
diff --git a/src/lib/components/chat/Messages/ResponseMessage/StatusHistory.svelte b/src/lib/components/chat/Messages/ResponseMessage/StatusHistory.svelte
index 5aaf774694..bb65bf331b 100644
--- a/src/lib/components/chat/Messages/ResponseMessage/StatusHistory.svelte
+++ b/src/lib/components/chat/Messages/ResponseMessage/StatusHistory.svelte
@@ -3,6 +3,7 @@
 	const i18n = getContext('i18n');
 
 	import StatusItem from './StatusHistory/StatusItem.svelte';
+	import equal from 'fast-deep-equal';
 	export let statusHistory = [];
 	export let expand = false;
 
@@ -21,10 +22,7 @@
 		status = history.at(-1);
 	}
 
-	$: if (
-		statusHistory.length !== history.length ||
-		JSON.stringify(statusHistory) !== JSON.stringify(history)
-	) {
+	$: if (!equal(statusHistory, history)) {
 		history = statusHistory;
 	}
 </script>
diff --git a/src/lib/components/chat/Messages/UserMessage.svelte b/src/lib/components/chat/Messages/UserMessage.svelte
index ec48a2e1ff..3b26dba1ff 100644
--- a/src/lib/components/chat/Messages/UserMessage.svelte
+++ b/src/lib/components/chat/Messages/UserMessage.svelte
@@ -7,6 +7,7 @@
 	import { user as _user } from '$lib/stores';
 	import { copyToClipboard as _copyToClipboard, formatDate } from '$lib/utils';
 	import { WEBUI_API_BASE_URL, WEBUI_BASE_URL } from '$lib/constants';
+	import equal from 'fast-deep-equal';
 
 	import Name from './Name.svelte';
 	import ProfileImage from './ProfileImage.svelte';
@@ -58,7 +59,7 @@
 		if (source) {
 			if (message.content !== source.content) {
 				message = structuredClone(source);
-			} else if (JSON.stringify(message) !== JSON.stringify(source)) {
+			} else if (!equal(message, source)) {
 				message = structuredClone(source);
 			}
 		}