Footer.astro: 最終更新日を和暦表記にする

Starlight の LastUpdated コンポーネント上書きが効かなかったため、Footer 内で令和・平成表記に整形して直接描画するようにした。

1 files changed, 30 insertions, 2 deletions

diff --git a/src/components/starlight/Footer.astro b/src/components/starlight/Footer.astro
index 5b59d09..e553e60 100644
--- a/src/components/starlight/Footer.astro
+++ b/src/components/starlight/Footer.astro
@@ -1,6 +1,5 @@
 ---
 import EditLink from 'virtual:starlight/components/EditLink';
-import LastUpdated from 'virtual:starlight/components/LastUpdated';
 import Pagination from 'virtual:starlight/components/Pagination';
 import config from 'virtual:starlight/user-config';
 import { Icon } from '@astrojs/starlight/components';
@@ -12,6 +11,28 @@ const caption = shareCaption(
   route.entry?.slug || route.id || '',
   route.entry?.data?.title,
 );
+
+/** Date を「令和8年9月22日 11:14」の形にする（ローカル時刻） */
+function toJapaneseDateTime(date: Date): string {
+  const y = date.getFullYear();
+  const m = date.getMonth() + 1;
+  const d = date.getDate();
+  let era = '昭和';
+  let n = y - 1925;
+  if (y > 2019 || (y === 2019 && m >= 5)) {
+    era = '令和';
+    n = y - 2018;
+  } else if (y >= 1989) {
+    era = '平成';
+    n = y - 1988;
+  }
+  const year = n === 1 ? `${era}元年` : `${era}${n}年`;
+  const hh = String(date.getHours()).padStart(2, '0');
+  const mm = String(date.getMinutes()).padStart(2, '0');
+  return `${year}${m}月${d}日 ${hh}:${mm}`;
+}
+
+const lastUpdated = route.lastUpdated;
 ---
 
 <footer class="sl-flex">
@@ -19,7 +40,14 @@ const caption = shareCaption(
 
   <div class="meta sl-flex">
     <EditLink />
-    <LastUpdated />
+    {
+      lastUpdated && (
+        <p>
+          {Astro.locals.t('page.lastUpdated')}{' '}
+          <time datetime={lastUpdated.toISOString()}>{toJapaneseDateTime(lastUpdated)}</time>
+        </p>
+      )
+    }
   </div>
   <Pagination />