From 71d81bde1d12aa386ec70be31cc86a37a7426bce Mon Sep 17 00:00:00 2001
From: Jacky Zhao <j.zhao2k19@gmail.com>
Date: Tue, 12 Sep 2023 19:18:44 -0700
Subject: [PATCH] feat: rss limit (closes #459)

---
 quartz/plugins/emitters/contentIndex.ts | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/quartz/plugins/emitters/contentIndex.ts b/quartz/plugins/emitters/contentIndex.ts
index f24ae6dc..bcb1e307 100644
--- a/quartz/plugins/emitters/contentIndex.ts
+++ b/quartz/plugins/emitters/contentIndex.ts
@@ -18,12 +18,14 @@ export type ContentDetails = {
 interface Options {
   enableSiteMap: boolean
   enableRSS: boolean
+  rssLimit?: number
   includeEmptyFiles: boolean
 }
 
 const defaultOptions: Options = {
   enableSiteMap: true,
   enableRSS: true,
+  rssLimit: 10,
   includeEmptyFiles: true,
 }
 
@@ -39,7 +41,7 @@ function generateSiteMap(cfg: GlobalConfiguration, idx: ContentIndex): string {
   return `<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:xhtml="http://www.w3.org/1999/xhtml">${urls}</urlset>`
 }
 
-function generateRSSFeed(cfg: GlobalConfiguration, idx: ContentIndex): string {
+function generateRSSFeed(cfg: GlobalConfiguration, idx: ContentIndex, limit?: number): string {
   const base = cfg.baseUrl ?? ""
   const root = `https://${base}`
 
@@ -53,13 +55,17 @@ function generateRSSFeed(cfg: GlobalConfiguration, idx: ContentIndex): string {
 
   const items = Array.from(idx)
     .map(([slug, content]) => createURLEntry(simplifySlug(slug), content))
+    .slice(0, limit ?? idx.size)
     .join("")
+
   return `<?xml version="1.0" encoding="UTF-8" ?>
 <rss version="2.0">
     <channel>
       <title>${escapeHTML(cfg.pageTitle)}</title>
       <link>${root}</link>
-      <description>Recent content on ${cfg.pageTitle}</description>
+      <description>${!!limit ? `Last ${limit} notes` : "Recent notes"} on ${
+        cfg.pageTitle
+      }</description>
       <generator>Quartz -- quartz.jzhao.xyz</generator>
       ${items}
     </channel>
@@ -102,7 +108,7 @@ export const ContentIndex: QuartzEmitterPlugin<Partial<Options>> = (opts) => {
       if (opts?.enableRSS) {
         emitted.push(
           await emit({
-            content: generateRSSFeed(cfg, linkIndex),
+            content: generateRSSFeed(cfg, linkIndex, opts.rssLimit),
             slug: "index" as FullSlug,
             ext: ".xml",
           }),