Aggregation on Many to many relations activerecord - ruby-on-rails

Question

I want to make ES aggregation on many to many activerecord model on rails but no way
My model :
class Foo < ApplicationRecord
searchkick
def search_data
{
bar: bar
}
end
has_many :bars
end
I have tried many solution but always get
{"active"=>{"doc_count_error_upper_bound"=>0, "sum_other_doc_count"=>0, "buckets"=>[]}}

Answer 1

The answer is add this :
def search_data
Attributes.merge(
bar_names: bar.map(&:name)
)
end

Answer 2

Here more about how to work with associated models, here is:
Item.rb (model):
# Relations
belongs_to :brand
## many-to-many relations between Items and Textures
has_many :item_attribute_for_textures
has_many :textures, through: :item_attribute_for_textures, :class_name => 'ItemAttribute::Texture'
# Searchkick
searchkick
def search_data
{
full_item_title: full_item_title,
brand: brand.try(:title),
texture: textures.map(&:title)
}
end
ItemController.rb:
def index
args = {}
args[:brand] = params[:brand] if params[:brand].present?
args[:texture] = params[:texture] if params[:texture].present?
query = params[:busca].presence || "*"
#items = Item.search query, where: args,
aggs: {
full_item_title: {},
brand: {},
texture: {}
}
end
and view index.html.erb:
<div class="row">
<div class="col-sm-2" style="font-size: 0.75rem">
<h5>Brands</h5>
<div>
<% #items.aggs["brand"]["buckets"].sort_by{ |b| b["key"] }.each do |bucket| %>
<div>
<% if params[:brand] == bucket["key"].to_s %>
<strong><%= bucket["key"] %></strong>
<% else %>
<%= link_to bucket["key"], request.params.merge(brand: bucket["key"]) %>
<% end %>
(<%= bucket["doc_count"] %>)
</div>
<% end %>
</div>
<hr>
<h5>Texture</h5>
<div>
<% #items.aggs["texture"]["buckets"].sort_by{ |b| b["key"] }.each do |bucket| %>
<div>
<% if params[:texture] == bucket["key"].to_s %>
<strong><%= bucket["key"] %></strong>
<% else %>
<%= link_to bucket["key"], request.params.merge(texture: bucket["key"]) %>
<% end %>
(<%= bucket["doc_count"] %>)
</div>
<% end %>
</div>
<hr>
</div>
</div>