enhance: nyaizeはクライアントで表示時に行うように

Resolve #12030

packages/frontend/src/components/global/MkMisskeyFlavoredMarkdown.ts

@@ -17,6 +17,7 @@ import MkSparkle from '@/components/MkSparkle.vue';
 import MkA from '@/components/global/MkA.vue';
 import { host } from '@/config.js';
 import { defaultStore } from '@/store.js';
+import { nyaize } from '@/scripts/nyaize.js';
 
 const QUOTE_STYLE = `
 display: block;
@@ -55,10 +56,13 @@ export default function(props: {
 	 * @param ast MFM AST
 	 * @param scale How times large the text is
 	 */
-	const genEl = (ast: mfm.MfmNode[], scale: number) => ast.map((token): VNode | string | (VNode | string)[] => {
+	const genEl = (ast: mfm.MfmNode[], scale: number, disableNyaize = false) => ast.map((token): VNode | string | (VNode | string)[] => {
 		switch (token.type) {
 			case 'text': {
-				const text = token.props.text.replace(/(\r\n|\n|\r)/g, '\n');
+				let text = token.props.text.replace(/(\r\n|\n|\r)/g, '\n');
+				if (!disableNyaize && props.author.isCat) {
+					text = nyaize(text);
+				}
 
 				if (!props.plain) {
 					const res: (VNode | string)[] = [];
@@ -260,7 +264,7 @@ export default function(props: {
 					key: Math.random(),
 					url: token.props.url,
 					rel: 'nofollow noopener',
-				}, genEl(token.children, scale))];
+				}, genEl(token.children, scale, true))];
 			}
 
 			case 'mention': {
@@ -299,11 +303,11 @@ export default function(props: {
 				if (!props.nowrap) {
 					return [h('div', {
 						style: QUOTE_STYLE,
-					}, genEl(token.children, scale))];
+					}, genEl(token.children, scale, true))];
 				} else {
 					return [h('span', {
 						style: QUOTE_STYLE,
-					}, genEl(token.children, scale))];
+					}, genEl(token.children, scale, true))];
 				}
 			}
 
@@ -358,7 +362,7 @@ export default function(props: {
 			}
 
 			case 'plain': {
-				return [h('span', genEl(token.children, scale))];
+				return [h('span', genEl(token.children, scale, true))];
 			}
 
 			default: {

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');
+}