fix: broken canonical urls (#26)

Author: lmammino

src/Layout.astro

@@ -17,7 +17,6 @@ import {
   TWITTER_CREATOR,
   BOOK_AUTHORS,
   THEME_COLOR,
-  CANONICAL_URL,
 } from '@lib/const'
 
 export interface Props {
@@ -35,7 +34,7 @@ const {
   ogTitle = OG_TITLE,
   ogDescription = OG_DESCRIPTION,
   ogImage = OG_IMAGE,
-  canonical = CANONICAL_URL,
+  canonical,
 } = Astro.props
 ---
 
@@ -64,7 +63,7 @@ const {
     <meta name="theme-color" content={THEME_COLOR} />
 
     <!-- Canonical URL -->
-    <link rel="canonical" href={canonical} />
+    {canonical && <link rel="canonical" href={canonical} />}
 
     <!-- RSS Feed -->
     <link

src/components/blog/BlogLayout.astro

@@ -64,6 +64,7 @@ if (post.rendered?.metadata?.headings) {
   description={description}
   ogTitle={title}
   ogDescription={description}
+  canonical={`${SITE_URL}/blog/${post.id}`}
 >
   <main class="min-h-screen bg-base-100">
     <!-- Blog Header -->

src/lib/const.ts

@@ -39,7 +39,7 @@ export const BOOK_EDITION = 'Fourth Edition'
 export const BOOK_PUBLICATION_DATE = '2025-10-09'
 
 // Additional
-export const CANONICAL_URL = 'https://nodejsdesignpatterns.com'
+export const DEFAULT_CANONICAL_URL = 'https://nodejsdesignpatterns.com'
 export const THEME_COLOR = '#16a34a' // Green color from the design
 
 // Free chapter

src/pages/blog/index.astro

@@ -5,6 +5,7 @@ import BlogCard from '../../components/blog/BlogCard.astro'
 import Breadcrumb from '@components/blog/Breadcrumb.astro'
 import Footer from '@components/Footer.astro'
 import BookPromo from '@components/blog/BookPromo.astro'
+import { SITE_URL } from '@lib/const'
 
 // Get all blog posts, sorted by date (newest first)
 const posts = (await getCollection('blog')).sort(
@@ -21,6 +22,7 @@ const pageDescription =
   description={pageDescription}
   ogTitle="Blog - Node.js Design Patterns"
   ogDescription={pageDescription}
+  canonical={`${SITE_URL}/blog/`}
 >
   <main class="min-h-screen bg-base-100">
     <header class="bg-gradient-to-b from-primary/40 to-primary/10">

src/pages/index.astro

@@ -15,9 +15,10 @@ import FreeChapter from '@components/pages/Home/FreeChapter.astro'
 import Faq from '@components/pages/Home/Faq.astro'
 import Navigation from '@components/Navigation.astro'
 import Footer from '@components/Footer.astro'
+import { DEFAULT_CANONICAL_URL } from '@lib/const'
 ---
 
-<Layout>
+<Layout canonical={`${DEFAULT_CANONICAL_URL}/`}>
   <Navigation />
   <Hero />
   <Counters />