Example of monkey patching the ShopifyAPI gem

shopify_api_ext.rb

module ShopifyAPI
  class Product
    def prices
      variants.collect(&:price).collect(&:to_f)
    end

    def price_min
      prices.min
    end

    def price_max
      prices.max
    end

    def available?
      variants.map(&:inventory_quantity).sum > 0
    end
  end
end