Add separate method for constructing chapters json

src/invidious/routes/api/v1/videos.cr

@@ -434,34 +434,7 @@ module Invidious::Routes::API::V1::Videos
     if format == "json"
       env.response.content_type = "application/json"
 
-      response = JSON.build do |json|
+      response = Invidious::Videos::Chapters.to_json(chapters, video.automatically_generated_chapters?.as(Bool))
-        json.object do
-          json.field "chapters" do
-            json.field "autoGenerated", video.automatically_generated_chapters?
-            json.array do
-              chapters.each do |chapter|
-                json.object do
-                  json.field "title", chapter.title
-                  json.field "startMs", chapter.start_ms
-                  json.field "endMs", chapter.end_ms
-
-                  json.field "thumbnails" do
-                    json.array do
-                      chapter.thumbnails.each do |thumbnail|
-                        json.object do
-                          json.field "url", thumbnail["url"]
-                          json.field "width", thumbnail["width"]
-                          json.field "height", thumbnail["height"]
-                        end
-                      end
-                    end
-                  end
-                end
-              end
-            end
-          end
-        end
-      end
 
       return response
     else

src/invidious/videos/chapters.cr

@@ -83,4 +83,43 @@ module Invidious::Videos::Chapters
       end
     end
   end
+
+  def self.to_json(json : JSON::Builder, chapters : Array(Chapter), auto_generated? : Bool)
+    json.field "autoGenerated", auto_generated?.to_s
+    json.field "chapters" do
+      json.array do
+        chapters.each do |chapter|
+          json.object do
+            json.field "title", chapter.title
+            json.field "startMs", chapter.start_ms
+            json.field "endMs", chapter.end_ms
+
+            json.field "thumbnails" do
+              json.array do
+                chapter.thumbnails.each do |thumbnail|
+                  json.object do
+                    json.field "url", thumbnail["url"]
+                    json.field "width", thumbnail["width"]
+                    json.field "height", thumbnail["height"]
+                  end
+                end
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+
+  def self.to_json(chapters : Array(Chapter), auto_generated? : Bool)
+    JSON.build do |json|
+      json.object do
+        json.field "chapters" do
+          json.object do
+            to_json(json, chapters, auto_generated?)
+          end
+        end
+      end
+    end
+  end
 end