6 files changed, 19 insertions, 22 deletions
diff --git a/nuldoc-src/pages/about.ts b/nuldoc-src/pages/about.ts
index adf4d73..459b88c 100644
--- a/nuldoc-src/pages/about.ts
+++ b/nuldoc-src/pages/about.ts
@@ -4,6 +4,7 @@ import { pageLayout } from "../components/page_layout.ts";
 import { Config } from "../config.ts";
 import { el, text } from "../dom.ts";
 import { Page } from "../page.ts";
+import { dateToString } from "../revision.ts";
 import { getPostCreatedDate } from "./post.ts";
 import { SlidePage } from "./slide.ts";
 
@@ -125,7 +126,7 @@ export async function generateAboutPage(
                     [["href", slide.href]],
                     text(
                       `${
-                        getPostCreatedDate(slide)
+                        dateToString(getPostCreatedDate(slide))
                       }: ${slide.event} (${slide.talkType})`,
                     ),
                   ),
diff --git a/nuldoc-src/pages/post.ts b/nuldoc-src/pages/post.ts
index 0bc313b..d870e99 100644
--- a/nuldoc-src/pages/post.ts
+++ b/nuldoc-src/pages/post.ts
@@ -6,7 +6,7 @@ import { Config } from "../config.ts";
 import { el, Element, text } from "../dom.ts";
 import { Document } from "../docbook/document.ts";
 import { Page } from "../page.ts";
-import { Revision } from "../revision.ts";
+import { Date, dateToString, Revision } from "../revision.ts";
 
 export interface PostPage extends Page {
   title: string;
@@ -15,11 +15,11 @@ export interface PostPage extends Page {
   revisions: Revision[];
 }
 
-export function getPostCreatedDate(page: { revisions: Revision[] }): string {
+export function getPostCreatedDate(page: { revisions: Revision[] }): Date {
   return page.revisions[0].date;
 }
 
-export function getPostUpdatedDate(page: { revisions: Revision[] }): string {
+export function getPostUpdatedDate(page: { revisions: Revision[] }): Date {
   return page.revisions[page.revisions.length - 1].date;
 }
 
@@ -87,8 +87,8 @@ export async function generatePostPage(
                   [["class", "revision"]],
                   el(
                     "time",
-                    [["datetime", rev.date]],
-                    text(rev.date),
+                    [["datetime", dateToString(rev.date)]],
+                    text(dateToString(rev.date)),
                   ),
                   text(`: ${rev.remark}`),
                 )
@@ -113,9 +113,7 @@ export async function generatePostPage(
 
   const html = await pageLayout(
     {
-      metaCopyrightYear: parseInt(
-        getPostCreatedDate(doc).substring(0, 4),
-      ),
+      metaCopyrightYear: getPostCreatedDate(doc).year,
       metaDescription: doc.summary,
       metaKeywords: doc.tags.map((slug) =>
         (config.blog.tagLabels as { [key: string]: string })[slug]
diff --git a/nuldoc-src/pages/post_list.ts b/nuldoc-src/pages/post_list.ts
index e8f27ee..498b3ef 100644
--- a/nuldoc-src/pages/post_list.ts
+++ b/nuldoc-src/pages/post_list.ts
@@ -5,6 +5,7 @@ import { postPageEntry } from "../components/post_page_entry.ts";
 import { Config } from "../config.ts";
 import { el, text } from "../dom.ts";
 import { Page } from "../page.ts";
+import { dateToString } from "../revision.ts";
 import { getPostCreatedDate, PostPage } from "./post.ts";
 
 export type PostListPage = Page;
@@ -32,8 +33,8 @@ export async function generatePostListPage(
         ),
       ),
       ...Array.from(posts).sort((a, b) => {
-        const ta = getPostCreatedDate(a);
-        const tb = getPostCreatedDate(b);
+        const ta = dateToString(getPostCreatedDate(a));
+        const tb = dateToString(getPostCreatedDate(b));
         if (ta > tb) return -1;
         if (ta < tb) return 1;
         return 0;
diff --git a/nuldoc-src/pages/slide.ts b/nuldoc-src/pages/slide.ts
index 2b7e202..f2955af 100644
--- a/nuldoc-src/pages/slide.ts
+++ b/nuldoc-src/pages/slide.ts
@@ -5,7 +5,7 @@ import { pageLayout } from "../components/page_layout.ts";
 import { Config } from "../config.ts";
 import { el, text } from "../dom.ts";
 import { Page } from "../page.ts";
-import { Revision } from "../revision.ts";
+import { dateToString, Revision } from "../revision.ts";
 import { Slide } from "../slide/slide.ts";
 import { getPostCreatedDate } from "./post.ts";
 
@@ -82,8 +82,8 @@ export async function generateSlidePage(
                   [["class", "revision"]],
                   el(
                     "time",
-                    [["datetime", rev.date]],
-                    text(rev.date),
+                    [["datetime", dateToString(rev.date)]],
+                    text(dateToString(rev.date)),
                   ),
                   text(`: ${rev.remark}`),
                 )
@@ -119,9 +119,7 @@ export async function generateSlidePage(
 
   const html = await pageLayout(
     {
-      metaCopyrightYear: parseInt(
-        getPostCreatedDate(slide).substring(0, 4),
-      ),
+      metaCopyrightYear: getPostCreatedDate(slide).year,
       metaDescription: slide.title,
       metaKeywords: slide.tags.map((slug) =>
         (config.blog.tagLabels as { [key: string]: string })[slug]
diff --git a/nuldoc-src/pages/slide_list.ts b/nuldoc-src/pages/slide_list.ts
index 18bea1f..5031436 100644
--- a/nuldoc-src/pages/slide_list.ts
+++ b/nuldoc-src/pages/slide_list.ts
@@ -5,6 +5,7 @@ import { slidePageEntry } from "../components/slide_page_entry.ts";
 import { Config } from "../config.ts";
 import { el, text } from "../dom.ts";
 import { Page } from "../page.ts";
+import { dateToString } from "../revision.ts";
 import { getPostCreatedDate } from "./post.ts";
 import { SlidePage } from "./slide.ts";
 
@@ -33,8 +34,8 @@ export async function generateSlideListPage(
         ),
       ),
       ...Array.from(slides).sort((a, b) => {
-        const ta = getPostCreatedDate(a);
-        const tb = getPostCreatedDate(b);
+        const ta = dateToString(getPostCreatedDate(a));
+        const tb = dateToString(getPostCreatedDate(b));
         if (ta > tb) return -1;
         if (ta < tb) return 1;
         return 0;
diff --git a/nuldoc-src/pages/tag.ts b/nuldoc-src/pages/tag.ts
index fbab8b1..cb60d21 100644
--- a/nuldoc-src/pages/tag.ts
+++ b/nuldoc-src/pages/tag.ts
@@ -40,9 +40,7 @@ export async function generateTagPage(
 
   const html = await pageLayout(
     {
-      metaCopyrightYear: parseInt(
-        getPostCreatedDate(pages[pages.length - 1]).substring(0, 4),
-      ),
+      metaCopyrightYear: getPostCreatedDate(pages[pages.length - 1]).year,
       metaDescription: `タグ「${tagLabel}」のついた記事またはスライドの一覧`,
       metaKeywords: [tagLabel],
       metaTitle: `${pageTitle} | ${config.blog.siteName}`,