Hide empty product filter options?

[octoxan]

Added a product filter for color, and while it works, it also shows filters for options that have no associated products. Trying to make it so that if a client removes all the grays from the category, that gray does not stay as an option.

Here's what's working so far:

module Spree::Core::ProductFilters
  Spree::OptionType.where("name like '%color%'").each do |ot|
    filter_name = ot.name.underscore.parameterize

    Spree::Product.add_search_scope filter_name do |*opts|
      Spree::Product.joins(variants: :option_values).where(option_values: { presentation: opts.first })
    end

    define_singleton_method("#{filter_name}_filter") do
      conds = ot.option_values.pluck(:presentation)
      {
        name: ot.presentation,
        scope: filter_name,
        type: 'color',
        labels: conds.map { |key, _value| [key, key] }
      }
    end
  end
end