Refactor site generation into a modular content pipeline

feed.js

@@ -0,0 +1,56 @@
+import { escapeHtml } from './html.js'
+import { siteName, siteUrl } from './site.config.js'
+
+export const toSitemapDate = (iso) => (iso ? iso.slice(0, 10) : '')
+
+const toRssDate = (iso) => {
+  if (!iso) return ''
+  const date = new Date(iso)
+  return Number.isNaN(date.valueOf()) ? '' : date.toUTCString()
+}
+
+export const renderFeed = (items) => {
+  const lastBuild = toRssDate(items.find((item) => item.date)?.date) || new Date().toUTCString()
+  const itemXml = items
+    .map((item) => {
+      const loc = `${siteUrl}/${item.dir}/${item.name}/`
+      const description = item.description
+      const pubDate = toRssDate(item.date)
+      return `<item>
+      <title>${escapeHtml(item.title)}</title>
+      <link>${escapeHtml(loc)}</link>
+      <guid isPermaLink="true">${escapeHtml(loc)}</guid>
+      ${pubDate ? `<pubDate>${escapeHtml(pubDate)}</pubDate>` : ''}
+      <category>${escapeHtml(item.dir)}</category>
+      ${description ? `<description>${escapeHtml(description)}</description>` : ''}
+    </item>`
+    })
+    .join('\n    ')
+
+  return `<?xml version="1.0" encoding="UTF-8"?>
+<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
+  <channel>
+    <title>${escapeHtml(siteName)}</title>
+    <link>${escapeHtml(`${siteUrl}/`)}</link>
+    <description>${escapeHtml(`Notes and posts from ${siteName}`)}</description>
+    <language>en-US</language>
+    <atom:link href="${escapeHtml(`${siteUrl}/feed.xml`)}" rel="self" type="application/rss+xml"/>
+    <lastBuildDate>${escapeHtml(lastBuild)}</lastBuildDate>
+    ${itemXml}
+  </channel>
+</rss>
+`
+}
+
+export const renderSitemap = (urls) => `<?xml version="1.0" encoding="UTF-8"?>
+<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+${urls
+  .map(({ loc, lastmod }) => {
+    const modified = lastmod ? `\n    <lastmod>${escapeHtml(lastmod)}</lastmod>` : ''
+    return `  <url>
+    <loc>${escapeHtml(loc)}</loc>${modified}
+  </url>`
+  })
+  .join('\n')}
+</urlset>
+`