feat(feed): Support custom feedUrl for feeds and use it as the self-link in RSS/Atom/JSON; update docs

readme.md

@@ -7,6 +7,7 @@
 ## Features ✨
 
 - 🎯 **Full TypeScript Support** - Complete type definitions for all feed formats
+- 🌐 **Cross-Platform** - Works in Node.js, Bun, Deno, and browsers
 - 📡 **Multiple Feed Formats** - RSS 2.0, Atom 1.0, JSON Feed 1.0, and Podcast RSS
 - 🎙️ **Modern Podcast Support** - iTunes tags, Podcast 2.0 namespace (guid, medium, locked, persons, transcripts, funding)
 - 🔒 **Built-in Validation** - Comprehensive validation for URLs, emails, domains, and timestamps
@@ -57,6 +58,30 @@ const atom = feed.exportAtomFeed();
 const json = feed.exportJsonFeed();
 ```
 
+### Custom Feed URL
+
+You can specify a custom URL for your feed's self-reference instead of the default `https://${domain}/feed.xml`:
+
+```typescript
+const feed = smartfeed.createFeed({
+  domain: 'example.com',
+  title: 'My Blog',
+  description: 'Latest posts',
+  category: 'Technology',
+  company: 'Example Inc',
+  companyEmail: 'hello@example.com',
+  companyDomain: 'https://example.com',
+  feedUrl: 'https://cdn.example.com/feeds/main.xml' // Custom feed URL
+});
+
+// The feedUrl will be used in:
+// - RSS: <atom:link href="..." rel="self">
+// - Atom: <link href="..." rel="self">
+// - JSON Feed: "feed_url" field
+```
+
+This is particularly useful when your feed is hosted on a CDN or different domain than your main site.
+
 ### Creating a Podcast Feed
 
 ```typescript
@@ -183,6 +208,7 @@ Creates a standard feed (RSS/Atom/JSON).
 - `company` (string) - Company/organization name
 - `companyEmail` (string) - Contact email
 - `companyDomain` (string) - Company website URL (absolute)
+- `feedUrl` (string, optional) - Custom URL for the feed's self-reference (defaults to `https://${domain}/feed.xml`)
 
 #### `createPodcastFeed(options: IPodcastFeedOptions): PodcastFeed`