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ruby-on-railsnestedcocoon-gem

Count nested item before save

Let have Order and Item models.

class Order < ApplicationRecord
  has_many :items, inverse_of: :order, dependent: :delete_all

  before_save do
    self.packed_volume = compute_packed_volume
  end

  private

  def compute_packed_volume
    items.count * 0.1O
  end
end

And

class Item < ApplicationRecord
  belongs_to :order, inverse_of: :items
end

The problem is that items.count is equals to 0 since items are not yet created. How can we get the number of items that will be created to used it when we create an order?

Solution

  • Try size instead, it won't run a query

    items.size * 0.1O

    Hope that helps!