From 5fd9db873900f96e9822a5c5e7e368ae368c1749 Mon Sep 17 00:00:00 2001
From: Algorithm5838 <108630393+Algorithm5838@users.noreply.github.com>
Date: Wed, 1 Apr 2026 01:19:47 +0300
Subject: [PATCH] perf: replace JS transition with CSS animation in
 CodespanToken (#23258)

---
 .../MarkdownInlineTokens/CodespanToken.svelte | 40 ++++++++++---------
 1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/src/lib/components/chat/Messages/Markdown/MarkdownInlineTokens/CodespanToken.svelte b/src/lib/components/chat/Messages/Markdown/MarkdownInlineTokens/CodespanToken.svelte
index c0b1ec327..1de3f13f6 100644
--- a/src/lib/components/chat/Messages/Markdown/MarkdownInlineTokens/CodespanToken.svelte
+++ b/src/lib/components/chat/Messages/Markdown/MarkdownInlineTokens/CodespanToken.svelte
@@ -1,7 +1,6 @@
 <script lang="ts">
 	import { copyToClipboard, unescapeHtml } from '$lib/utils';
 	import { toast } from 'svelte-sonner';
-	import { fade } from 'svelte/transition';
 
 	import { getContext } from 'svelte';
 
@@ -13,21 +12,24 @@
 
 <!-- svelte-ignore a11y-click-events-have-key-events -->
 <!-- svelte-ignore a11y-no-noninteractive-element-interactions -->
-{#if done}
-	<code
-		class="codespan cursor-pointer"
-		on:click={() => {
-			copyToClipboard(unescapeHtml(token.text));
-			toast.success($i18n.t('Copied to clipboard'));
-		}}>{unescapeHtml(token.text)}</code
-	>
-{:else}
-	<code
-		transition:fade={{ duration: 100 }}
-		class="codespan cursor-pointer"
-		on:click={() => {
-			copyToClipboard(unescapeHtml(token.text));
-			toast.success($i18n.t('Copied to clipboard'));
-		}}>{unescapeHtml(token.text)}</code
-	>
-{/if}
+<code
+	class="codespan cursor-pointer {!done ? 'fade-in-token' : ''}"
+	on:click={() => {
+		copyToClipboard(unescapeHtml(token.text));
+		toast.success($i18n.t('Copied to clipboard'));
+	}}>{unescapeHtml(token.text)}</code
+>
+
+<style>
+	@keyframes fade-in-token {
+		from {
+			opacity: 0;
+		}
+		to {
+			opacity: 1;
+		}
+	}
+	.fade-in-token {
+		animation: fade-in-token 100ms ease-out;
+	}
+</style>