feat: 多语言将中文设置为默认的语言

src/i18n/index.ts

@@ -12,12 +12,14 @@ export function getCopy(lang: string | undefined): SiteCopy {
   return copies[DEFAULT_LANG];
 }
 
-/** Astro `getStaticPaths`：为四种语言各生成一页 */
+/** Astro `getStaticPaths`：默认语言生成无前缀路径，其他语言带前缀 */
 export function langStaticPaths() {
-  return LANGS.map((lang) => ({ params: { lang } }));
+  return LANGS.map((lang) => ({
+    params: { lang: lang === DEFAULT_LANG ? undefined : lang },
+  }));
 }
 
 export type { Lang } from './locales';
 export type { SiteCopy } from './types';
-export { LANGS, DEFAULT_LANG, htmlLang, langLabels, hrefFor, isLang } from './locales';
+export { LANGS, DEFAULT_LANG, htmlLang, langLabels, hrefFor, isLang, resolveLang } from './locales';
 export type { RouteKey } from './locales';

src/i18n/locales.ts

@@ -26,6 +26,12 @@ export function isLang(value: string | undefined): value is Lang {
 export type RouteKey = '' | 'teaching-philosophy' | 'curriculum' | 'faculty' | 'about';
 
 export function hrefFor(lang: Lang, segment: RouteKey): string {
-  if (!segment) return `/${lang}`;
-  return `/${lang}/${segment}`;
+  const prefix = lang === DEFAULT_LANG ? '' : `/${lang}`;
+  if (!segment) return prefix || '/';
+  return `${prefix}/${segment}`;
+}
+
+/** 从 [...lang] rest 参数解析语言，undefined 时返回默认语言 */
+export function resolveLang(param: string | undefined): Lang {
+  return isLang(param) ? param : DEFAULT_LANG;
 }