how to filter association with grouped select in Rails

Question

Team has_many :users
User belongs_to :team

I can also scope my users:

scope :active, -> (active) {where active: active }

In my form, I want a select of active users grouped by teams.

<%= f.association :user, collection: Team.all, as: :grouped_select, group_method: :users %>

gives me a grouped select of users (both active and non active) by teams.

<%= f.association :user, collection: User.where(active: true) %>

gives me a select of active users.

I can't figure out the syntax to combine the two. Thanks !

Answer 1

I've added a method in my user.rb :

def self.for_select
  Team.active.map do |team|
    [team.name, team.users.active(true).map { |u| [u.name, u.id] } ]
  end
end

and used a grouped_option_for_select in my form :

<%= f.select :user_id, grouped_options_for_select(User.for_select) %>

This blog post was very helpful : http://andrewradev.com/2011/05/25/grouped-select-helper-methods-in-rails/

Anyone has a better way ?