canonical / canonical-absent

---
// Local sample values make this existing draft renderable for comparison.
// The original source is preserved in metadata-cases/original-index.astro.txt.
import { assetHref, normalizeBase } from '../metadata-cases/cases';
const base = import.meta.env.BASE_URL;
const fullTitle = 'Current metadata draft';
const description = 'The existing head structure with local sample values for comparison.';
const styleURL = assetHref('reference.css', base);
const SITE_NAME = 'Metadata research';
const noindex = false;
const canonical = new URL(normalizeBase(base), Astro.url.origin).href;
const ogType = 'website' as 'website' | 'article';
const ogImage = new URL(assetHref('social-red.png', base), Astro.url.origin).href;
const publishedTime = undefined as Date | undefined;
const modifiedTime = undefined as Date | undefined;
const jsonLd = undefined as Record<string, unknown> | undefined;
---

<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width" />
    <title>{fullTitle}</title>
    <meta name="color-scheme" content="dark light" />
    <link rel="stylesheet" href={styleURL} />
    <link rel="icon" href={`${normalizeBase(base)}favicon.ico`} />
    <!-- sizes="32x32" -->
    <link rel="icon" type="image/svg+xml" href={assetHref('icon-blue.svg', base)} />

    <link rel="apple-touch-icon" href={assetHref('apple-touch-icon.png', base)} />
    <link rel="manifest" href={assetHref('app.webmanifest', base)} />

    {!noindex && <link rel="canonical" href={canonical} />}
    <meta name="description" content={description} />
    {noindex && <meta name="robots" content="noindex" />}
    {!noindex && (
      <>
        <meta property="og:site_name" content={SITE_NAME} />
        <meta property="og:type" content={ogType} />
        <meta property="og:url" content={canonical} />
        <meta property="og:title" content={fullTitle} />
        <meta property="og:description" content={description} />
        <meta property="og:image" content={ogImage} />
        <meta name="twitter:card" content="summary_large_image" />
        {ogType === "article" && publishedTime && (
          <meta
            property="article:published_time"
            content={publishedTime.toISOString()}
          />
        )}
        {ogType === "article" && modifiedTime && (
          <meta
            property="article:modified_time"
            content={modifiedTime.toISOString()}
          />
        )}
      </>
    )}
    {jsonLd && (
      <script
        type="application/ld+json"
        is:inline
        set:html={JSON.stringify(jsonLd).replace(/</g, "\\u003c")}
      />
    )}
    <slot name="head" />
  </head>
  <body>
    <h1>Astro</h1>
    <p><a href={`${normalizeBase(base)}cases/`}>Compare metadata cases</a></p>
  </body>
</html>

{
  "canonical": null
}