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)
 
    respond_to do |format|
      if @line_item.save
        format.html { redirect_to store_url }
        format.js   { @current_item = @line_item }
        format.json { render :show,
          status: :created, location: @line_item }
      else
        format.html { render :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
# Use jquery as the JavaScript library
gem 'jquery-rails'
gem 'jquery-ui-rails'

Install the gem

bundle install --local
Resolving dependencies...
Using rake 10.3.2
Using i18n 0.6.11
Using json 1.8.1
Using minitest 5.4.3
Using thread_safe 0.3.4
Using tzinfo 1.2.2
Using activesupport 4.1.8 from source at /home/rubys/git/rails
Using builder 3.2.2
Using erubis 2.7.0
Using actionview 4.1.8 from source at /home/rubys/git/rails
Using rack 1.5.2
Using rack-test 0.6.2
Using actionpack 4.1.8 from source at /home/rubys/git/rails
Using mime-types 2.4.3
Using mail 2.6.3
Using actionmailer 4.1.8 from source at /home/rubys/git/rails
Using activemodel 4.1.8 from source at /home/rubys/git/rails
Using arel 5.0.1.20140414130214
Using activerecord 4.1.8 from source at /home/rubys/git/rails
Using bundler 1.7.6
Using coffee-script-source 1.8.0
Using execjs 2.2.2
Using coffee-script 2.3.0
Using thor 0.19.1
Using railties 4.1.8 from source at /home/rubys/git/rails
Using coffee-rails 4.1.0 from source at /home/rubys/git/coffee-rails
Using hike 1.2.3
Using multi_json 1.10.1
Using jbuilder 2.2.5
Using jquery-rails 3.1.2
Using jquery-ui-rails 5.0.2
Using tilt 1.4.1
Using sprockets 2.12.3
Using sprockets-rails 2.1.4 from source at /home/rubys/git/sprockets-rails
Using rails 4.1.8 from source at /home/rubys/git/rails
Using rdoc 4.1.2
Using sass 3.4.8
Using sass-rails 5.0.0.beta1 from source at /home/rubys/git/sass-rails
Using sdoc 0.4.1
Using spring 1.1.3
Using sqlite3 1.3.10
Using turbolinks 2.5.2
Using uglifier 2.5.3
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 compiled file.
//
// Read Sprockets README
// (https://github.com/sstephenson/sprockets#sprockets-directives) for details
// about supported directives.
//
//= require jquery
//= require jquery-ui/effect-blind
//= require jquery_ujs
//= require turbolinks
//= require_tree .

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