如何在Rails中获取子类数组

ParentClass.descendants
# 返回所有直接子类的数组

# 在config/initializers/preload_classes.rb
Rails.application.config.after_initialize do
  Dir.glob(Rails.root.join('app/models/**/*.rb')).each { |f| require f }
end

def all_descendants(parent)
  parent.descendants.flat_map { |child| [child] + all_descendants(child) }
end

all_descendants(ParentClass)

class Vehicle; end
class Car < Vehicle; end
class Truck < Vehicle; end
class Sedan < Car; end

Vehicle.descendants 
# => [Car, Truck, Sedan] (注意顺序可能不同)

ObjectSpace.each_object(Class).select { |c| c < ParentClass }