Extract methods to get objects in attachment forms

app/components/documents/fields_component.rb

@@ -8,11 +8,15 @@ class Documents::FieldsComponent < ApplicationComponent
 
   private
 
-    def document_attachment_file_name(document)
+    def document
+      f.object
+    end
+
+    def document_attachment_file_name
       document.attachment_file_name
     end
 
-    def render_destroy_document_link(document)
+    def render_destroy_document_link
       if !document.persisted? && document.cached_attachment.present?
         link_to t("documents.form.delete_button"),
           direct_upload_destroy_path(
@@ -29,25 +33,25 @@ class Documents::FieldsComponent < ApplicationComponent
       end
     end
 
-    def render_attachment(document)
+    def render_attachment
       klass = document.persisted? || document.cached_attachment.present? ? " hide" : ""
       f.file_field :attachment,
         label_options: { class: "button hollow #{klass}" },
-        accept: accepted_content_types_extensions(document.documentable_type.constantize),
+        accept: accepted_content_types_extensions,
         class: "js-document-attachment",
         data: {
-          url: document_direct_upload_path(document),
+          url: document_direct_upload_path,
           nested_document: true
         }
     end
 
-    def document_direct_upload_path(document)
+    def document_direct_upload_path
       direct_uploads_path("direct_upload[resource_type]": document.documentable_type,
                           "direct_upload[resource_id]": document.documentable_id,
                           "direct_upload[resource_relation]": "documents")
     end
 
-    def accepted_content_types_extensions(documentable_class)
+    def accepted_content_types_extensions
       Setting.accepted_content_types_for("documents").map { |content_type| ".#{content_type}" }.join(",")
     end
 end