How associations are updated with Synchromesh and ReactiveRecord - react.rb

Question

How do you get Synchromesh to update Reactive Record associations?
If you consider the following model:
# models/public/post.rb
class Post < ActiveRecord::Base
has_many :comments
end
# models/public/comments.rb
class Comment < ActiveRecord::Base
belongs_to :post
end
And a component that is rendering all Posts and Comments:
def render
ul do
Todo.all.each do |todo|
li { todo.title }
ul do
todo.things.each do |thing|
li { thing.name }
end
end
end
end
The behaviour I am seeing is that any update to a Post or Comment is correctly pushed to the client and the component renders the update correctly.
However, if a new Thing is created (for a Todo being rendered), the new record arrives as a pushed notification but the list of things is not updated dynamically. (A page refresh does render the new Thing).
I have tried adding a scope to Todo but this does not make a difference.
scope :all_with_things, -> () { joins(:things) }, [Thing]
What is the best way of getting ReactiveRecord and Synchromesh to recognise a new Thing belonging to a Todo?

Answer 1

I believe I worked out the answer. You need to use a scope when rendering the collection.
So in the model:
# models/public/comments.rb
class Comment < ActiveRecord::Base
belongs_to :post
scope :for_post, -> (post_id) { where(post_id: post_id) }
end
And then when rendering the collection:
Todo.all.each do |todo|
li { todo.title }
ul do
Comment.for_post(post.id).each do |comment|
li { comment.body }
end
end
end
And with that it all works.