From 9510cd70c14ce9a80962ade5dd1702f7d2e2218e Mon Sep 17 00:00:00 2001
From: skirtle <65301168+skirtles-code@users.noreply.github.com>
Date: Fri, 19 Jan 2024 09:15:06 +0000
Subject: [PATCH] docs: add a canonical URL `<link>` example (#3473)

---
 docs/reference/site-config.md | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/docs/reference/site-config.md b/docs/reference/site-config.md
index 1cf9d726..f23082f8 100644
--- a/docs/reference/site-config.md
+++ b/docs/reference/site-config.md
@@ -645,6 +645,23 @@ export default {
 }
 ```
 
+#### Example: Adding a canonical URL `<link>`  
+
+```ts
+export default {
+  transformHead({ page }) {
+    // Skip the 404 page
+    if (page !== '404.md') {
+      const canonicalUrl = `https://example.com/${page}`
+        .replace(/index\.md$/, '')
+        .replace(/\.md$/, '.html')
+
+      return [['link', { rel: 'canonical', href: canonicalUrl }]]
+    }
+  }
+}
+```
+
 ### transformHtml
 
 - Type: `(code: string, id: string, context: TransformContext) => Awaitable<string | void>`