From 16795f18a7d9672f408b81228db67c7df77417f6 Mon Sep 17 00:00:00 2001
From: easrng <easrng@gmail.com>
Date: Sun, 14 Jul 2024 06:31:30 -0600
Subject: [PATCH] Enhance(frontend): Allow negative delay in MFM (#14200)

Co-authored-by: easrng <me@easrng.net>
---
 CHANGELOG.md                                                    | 1 +
 .../frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e50dbfec9b..83f2261c1d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@
 - Fix: 配信停止したインスタンス一覧が見れなくなる問題を修正
 - Fix: Dockerコンテナの立ち上げ時に`pnpm`のインストールで固まることがある問題
 - Fix: デフォルトテーマに無効なテーマコードを入力するとUIが使用できなくなる問題を修正
+- Enhance: Allow negative delay for MFM animation elements (`tada`, `jelly`, `twitch`, `shake`, `spin`, `jump`, `bounce`, `rainbow`)
 
 ### Client
 - Enhance: 内蔵APIドキュメントのデザイン・パフォーマンスを改善
diff --git a/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts b/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts
index cab8d9c704..0d869892bd 100644
--- a/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts
+++ b/packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts
@@ -65,7 +65,7 @@ export default function (props: MfmProps, { emit }: { emit: SetupContext<MfmEven
 	const validTime = (t: string | boolean | null | undefined) => {
 		if (t == null) return null;
 		if (typeof t === 'boolean') return null;
-		return t.match(/^[0-9.]+s$/) ? t : null;
+		return t.match(/^\-?[0-9.]+s$/) ? t : null;
 	};
 
 	const validColor = (c: unknown): string | null => {