enhance: nyaizeはクライアントで表示時に行うように

Resolve #12030

packages/frontend/src/scripts/nyaize.ts

@@ -0,0 +1,20 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and other misskey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export function nyaize(text: string): string {
+	return text
+		// ja-JP
+		.replaceAll('な', 'にゃ').replaceAll('ナ', 'ニャ').replaceAll('ﾅ', 'ﾆｬ')
+		// en-US
+		.replace(/(?<=n)a/gi, x => x === 'A' ? 'YA' : 'ya')
+		.replace(/(?<=morn)ing/gi, x => x === 'ING' ? 'YAN' : 'yan')
+		.replace(/(?<=every)one/gi, x => x === 'ONE' ? 'NYAN' : 'nyan')
+		// ko-KR
+		.replace(/[나-낳]/g, match => String.fromCharCode(
+			match.charCodeAt(0)! + '냐'.charCodeAt(0) - '나'.charCodeAt(0),
+		))
+		.replace(/(다$)|(다(?=\.))|(다(?= ))|(다(?=!))|(다(?=\?))/gm, '다냥')
+		.replace(/(야(?=\?))|(야$)|(야(?= ))/gm, '냥');
+}