Support multiple RSS feeds in alternates, and RSS feed titles

[danielcompton]

Goals

1. Add multiple RSS feeds as tags
2. Include different title attributes on each tag so they can be distinguished

Non-Goals

No response

Background

Many websites provide more than one RSS feed, e.g. https://wordpress.com/blog/2024/02/20/site-editor-updates/ contains

<link rel="alternate" type="application/rss+xml" title="WordPress.com Blog" href="https://wordpress.com/blog/feed/">
<link rel="alternate" type="application/rss+xml" title="WordPress.com News » Small Changes, Big Impact: A Look at What’s New In the WordPress Editor&nbsp; Comments Feed" href="https://wordpress.com/blog/2024/02/20/site-editor-updates/feed/">
<link rel="alternate" type="application/json+oembed" href="https://public-api.wordpress.com/oembed/?format=json&amp;url=https%3A%2F%2Fen.blog.wordpress.com%2F2024%2F02%2F20%2Fsite-editor-updates%2F&amp;for=wpcom-auto-discovery">
<link rel="alternate" type="application/xml+oembed" href="https://public-api.wordpress.com/oembed/?format=xml&amp;url=https%3A%2F%2Fen.blog.wordpress.com%2F2024%2F02%2F20%2Fsite-editor-updates%2F&amp;for=wpcom-auto-discovery">

Currently the docs show

export const metadata = {
  alternates: {
    canonical: 'https://nextjs.org',
    languages: {
      'en-US': 'https://nextjs.org/en-US',
      'de-DE': 'https://nextjs.org/de-DE',
    },
    media: {
      'only screen and (max-width: 600px)': 'https://nextjs.org/mobile',
    },
    types: {
      'application/rss+xml': 'https://nextjs.org/rss',
    },
  },
}

Leading to this HTML

<link rel="canonical" href="https://nextjs.org" />
<link rel="alternate" hreflang="en-US" href="https://nextjs.org/en-US" />
<link rel="alternate" hreflang="de-DE" href="https://nextjs.org/de-DE" />
<link
  rel="alternate"
  media="only screen and (max-width: 600px)"
  href="https://nextjs.org/mobile"
/>
<link
  rel="alternate"
  type="application/rss+xml"
  href="https://nextjs.org/rss"
/>

But there is no way to provide multiple RSS feeds of the same type because types has a map value, not an array.

Proposal

I'm not sure if this is the best syntax, but here is roughly what I'm imagining:

export const metadata = {
  alternates: {
    canonical: 'https://example.com',
    types: [
      {link: "https://example.com/feed", type: "application/atom+xml", title: "RSS"},
      {link: "https://example.com/feed.json", type: "application/feed+json", title: "JSON Feed"},
      {link: "https://example.com/feed/comments", type: "application/atom+xml", title: "Comments"}
    ],
  },
}

[Sothatsit]

For anyone else looking for this, this was implemented in PR 46700 in March, 2023.