Support JSON-LD named graph (#31288)

spec/lib/link_details_extractor_spec.rb

@@ -79,6 +79,16 @@ RSpec.describe LinkDetailsExtractor do
         },
       }.to_json
     end
+    let(:html) { <<~HTML }
+      <!doctype html>
+      <html>
+      <body>
+        <script type="application/ld+json">
+          #{ld_json}
+        </script>
+      </body>
+      </html>
+    HTML
 
     shared_examples 'structured data' do
       it 'extracts the expected values from structured data' do
@@ -224,21 +234,27 @@ RSpec.describe LinkDetailsExtractor do
           },
         }.to_json
       end
-      let(:html) { <<~HTML }
-        <!doctype html>
-        <html>
-        <body>
-          <script type="application/ld+json">
-            #{ld_json}
-          </script>
-        </body>
-        </html>
-      HTML
 
       it 'joins author names' do
         expect(subject.author_name).to eq 'Author 1, Author 2'
       end
     end
+
+    context 'with named graph' do
+      let(:ld_json) do
+        {
+          '@context' => 'https://schema.org',
+          '@graph' => [
+            '@type' => 'NewsArticle',
+            'headline' => "What's in a name",
+          ],
+        }.to_json
+      end
+
+      it 'descends into @graph node' do
+        expect(subject.title).to eq "What's in a name"
+      end
+    end
   end
 
   context 'when Open Graph protocol data is present' do