fix: same domain check with www for baseUrl

src/canonical/handler.js

@@ -352,7 +352,7 @@ export function validateCanonicalFormat(canonicalUrl, baseUrl, log) {
     }
 
     // Check if the canonical URL has the same domain as the base URL
-    if (url.hostname !== base.hostname) {
+    if (url.hostname !== base.hostname && url.hostname !== `www.${base.hostname}` && `www.${url.hostname}` !== base.hostname) {
       checks.push({
         check: CANONICAL_CHECKS.CANONICAL_URL_SAME_DOMAIN.check,
         success: false,

test/audits/canonical.test.js

@@ -325,6 +325,22 @@ describe('Canonical URL Tests', () => {
       expect(log.info).to.have.been.calledWith('Canonical URL  https://example.com uses a different protocol than base URL http://example.com');
     });
 
+    it('should pass when canonical URL and base URL are identical, regardless of the www prefix', () => {
+      const cases = [
+        { canonicalUrl: 'https://www.example.com', baseUrl: 'https://example.com' },
+        { canonicalUrl: 'https://example.com', baseUrl: 'https://www.example.com' },
+      ];
+
+      cases.forEach(({ canonicalUrl, baseUrl }) => {
+        const result = validateCanonicalFormat(canonicalUrl, baseUrl, log);
+
+        expect(result).to.deep.include({
+          check: 'canonical-url-same-domain',
+          success: true,
+        });
+      });
+    });
+
     it('should fail if the canonical URL is not absolute', () => {
       const canonicalUrl = '/relative/url';
       const baseUrl = 'http://example.com';