Agile Web Development with Rails, Edition 4

11.4 Iteration F4: Hide an Empty Cart 11.2 Iteration F2: Creating an AJAX-Based Cart

11.3 Iteration F3: Highlighting Changes

Assign the current item to be the line item in question

edit app/controllers/line_items_controller.rb
  def create
    product = Product.find(params[:product_id])
    @line_item = @cart.add_product(product.id)
    @line_item.product = product
 
    respond_to do |format|
      if @line_item.save
        format.html { redirect_to store_url }
        format.js   { @current_item = @line_item }
        format.json { render json: @line_item,
          status: :created, location: @line_item }
      else
        format.html { render action: "new" }
        format.json { render json: @line_item.errors,
          status: :unprocessable_entity }
      end
    end
  end

Add the id to the row in question

edit app/views/line_items/_line_item.html.erb
<% if line_item == @current_item %>
<tr id="current_item">
<% else %>
<tr>
<% end %>
  <td><%= line_item.quantity %>&times;</td>
  <td><%= line_item.product.title %></td>
  <td class="item_price"><%= number_to_currency(line_item.total_price) %></td>
</tr>

Animate the background color of that row

edit app/views/line_items/create.js.erb
$('#cart').html("<%= escape_javascript render(@cart) %>");
 
$('#current_item').css({'background-color':'#88ff88'}).
  animate({'background-color':'#114411'}, 1000);

Make the jquery-ui libraries available to the application

edit Gemfile
gem 'jquery-rails'
gem 'jquery-ui-rails'

Install the gem

bundle install --local
Resolving dependencies...
Using rake (10.2.1)
Using i18n (0.6.9)
Using multi_json (1.9.2)
Using activesupport (3.2.17) from source at /home/rubys/git/rails
Using builder (3.0.4)
Using activemodel (3.2.17) from source at /home/rubys/git/rails
Using erubis (2.7.0)
 
journey at /home/rubys/git/journey did not have a valid gemspec.
This prevents bundler from installing bins or native extensions, but that may not affect its functionality.
The validation message from Rubygems was:
  duplicate dependency on rdoc (~> 3.10, development), (~> 3.11) use:
    add_runtime_dependency 'rdoc', '~> 3.10', '~> 3.11'
Using journey (1.0.4.20120614141756) from source at /home/rubys/git/journey
Using rack (1.4.5)
Using rack-cache (1.2)
Using rack-test (0.6.2)
Using hike (1.2.3)
Using tilt (1.4.1)
Using sprockets (2.2.2)
Using actionpack (3.2.17) from source at /home/rubys/git/rails
Using mime-types (1.25.1)
Using polyglot (0.3.4)
Using treetop (1.4.15)
Using mail (2.5.4)
Using actionmailer (3.2.17) from source at /home/rubys/git/rails
Using arel (3.0.3.20131114190737) from source at /home/rubys/git/arel
Using tzinfo (0.3.39)
Using activerecord (3.2.17) from source at /home/rubys/git/rails
Using activeresource (3.2.17) from source at /home/rubys/git/rails
Using bundler (1.5.3)
Using coffee-script-source (1.7.0)
Using execjs (2.0.2)
Using coffee-script (2.2.0)
Using rack-ssl (1.3.4)
Using json (1.8.1)
Using rdoc (3.12.2)
Using thor (0.19.1)
Using railties (3.2.17) from source at /home/rubys/git/rails
Using coffee-rails (3.2.2) from source at /home/rubys/git/coffee-rails
Using jquery-rails (3.1.0)
Using jquery-ui-rails (4.2.0)
Using rails (3.2.17) from source at /home/rubys/git/rails
Using sass (3.3.4)
Using sass-rails (3.2.6) from source at /home/rubys/git/sass-rails
Using sqlite3 (1.3.9)
Using uglifier (2.5.0)
Your bundle is complete!
Use `bundle show [gemname]` to see where a bundled gem is installed.

Restart the server.

Pull in the blind effect from the jquery-ui libraries

edit app/assets/javascripts/application.js
// This is a manifest file that'll be compiled into application.js, which will
// include all the files listed below.
//
// Any JavaScript/Coffee file within this directory, lib/assets/javascripts,
// vendor/assets/javascripts, or vendor/assets/javascripts of plugins, if any,
// can be referenced here using a relative path.
//
// It's not advisable to add code directly here, but if you do, it'll appear at
// the bottom of the the compiled file.
//
// WARNING: THE FIRST BLANK LINE MARKS THE END OF WHAT'S TO BE PROCESSED, ANY
// BLANK LINE SHOULD GO AFTER THE REQUIRES BELOW.
//
//= require jquery
//= require jquery.ui.effect-blind
//= require jquery_ujs
//= require_tree .

11.4 Iteration F4: Hide an Empty Cart 11.2 Iteration F2: Creating an AJAX-Based Cart