perf: replace JSON.stringify equality with fast-deep-equal (#23370)

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);
 			}
 		}

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);
 			}

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>

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);
 			}
 		}