The Depot Application

9.3 Iteration D3: Highlighting Changes

edit app/models/cart.rb

class Cart

  attr_reader :items   # <wtf linkend="wtf.attr.accessor">attr_reader</wtf>

  def initialize

    @items = []

end

  def add_product(product)

    current_item = @items.find {|item| item.product == product}

    if current_item

      current_item.increment_quantity

    else

      current_item = CartItem.new(product)

      @items << current_item

end

    current_item

end

  def total_price

    @items.sum { |item| item.price }

end

end

edit app/controllers/store_controller.rb

  def add_to_cart

    product = Product.find(params[:id])

    @cart = find_cart

    @current_item = @cart.add_product(product)

    respond_to do |format|

      format.js

end

  rescue ActiveRecord::RecordNotFound

    logger.error("Attempt to access invalid product #{params[:id]}")

    redirect_to_index("Invalid product")

end

edit app/views/store/_cart_item.html.erb

<% if cart_item == @current_item %>

  <tr id="current_item">

<% else %>

  <tr>

<% end %>

  <td><%= cart_item.quantity %>&times;</td>

  <td><%=h cart_item.title %></td>

  <td class="item-price"><%= number_to_currency(cart_item.price) %></td>

</tr>

edit app/views/store/add_to_cart.js.rjs

page.replace_html("cart", :partial => "cart", :object => @cart)

page[:current_item].visual_effect :highlight,

                                  :startcolor => "#88ff88",

                                  :endcolor => "#114411"