ブログ記事一覧ページに、外部サイト記事も表示するようにしてみた

--- a/src/pages/blog/index.astro
+++ b/src/pages/blog/index.astro
@@ -6,15 +6,133 @@ import { SITE_TITLE, SITE_DESCRIPTION } from "../../consts";
 import { getCollection } from "astro:content";
 import FormattedDate from "../../components/FormattedDate.astro";

+const externalPosts = [
+  {
+    id: "external-1",
+    slug: "",
+    body: "",
+    collection: "external",
+    data: {
+      title: "VimでMarkdownの日本語メモを取るための設定をする",
+      pubDate: new Date("2017-04-27"),
+      url: "https://qiita.com/tkancf/items/e61b7c09def497204628",
+    },
+  },
+  {
+    id: "external-2",
+    slug: "",
+    body: "",
+    collection: "external",
+    data: {
+      title: "この1冊ですべてわかる 新版 コーチングの基本を読みました",
+      pubDate: new Date("2022-08-21"),
+      url: "https://tkancf.hateblo.jp/blog/%E3%81%93%E3%81%AE1%E5%86%8A%E3%81%A7%E3%81%99%E3%81%B9%E3%81%A6%E3%82%8F%E3%81%8B%E3%82%8B_%E6%96%B0%E7%89%88_%E3%82%B3%E3%83%BC%E3%83%81%E3%83%B3%E3%82%B0%E3%81%AE%E5%9F%BA%E6%9C%AC%E3%82%92%E8%AA%AD%E3%81%BF%E3%81%BE",
+    },
+  },
(中略)
+  {
+    id: "external-10",
+    slug: "",
+    body: "",
+    collection: "external",
+    data: {
+      title: "fish shellの初期設定覚え書き（PATHの設定とか）",
+      pubDate: new Date("2017-03-30"),
+      url: "https://tkancf.hateblo.jp/blog/2017/03/30",
+    },
+  },
+];
+
 const posts = (await getCollection("blog")).sort(
   (a, b) => b.data.pubDate.valueOf() - a.data.pubDate.valueOf()
 );
+
+const combinedPosts = [...posts, ...externalPosts].sort(
+  (a, b) => b.data.pubDate.valueOf() - a.data.pubDate.valueOf()
+);
 ---
@@ -40,10 +158,19 @@ const posts = (await getCollection("blog")).sort(
       <section>
         <ul>
           {
-            posts.map((post) => (
+            combinedPosts.map((post) => (
               <li>
                 <FormattedDate date={post.data.pubDate} />
-                <a href={`/blog/${post.slug}/`}>{post.data.title}</a>
+                <a
+                  href={
+                    post.collection === "external"
+                      ? post.data.url
+                      : `/blog/${post.slug}/`
+                  }
+                >
+                  {post.collection === "external" ? "(外部リンク): " : ""}
+                  {post.data.title}{" "}
+                </a>
               </li>
             ))
           }