Agile Web Development with Rails, Edition 5

11.5 Iteration F5: Broadcasting Updates 11.3 Iteration F3: Highlighting Changes

11.4 Iteration F4: Hide an Empty Cart

Add a blind down visual effect on the first item

edit app/views/line_items/create.js.erb
if ($('#cart tr').length == 1) { $('#cart').show('blind', 1000); }
 
$('#cart').html("<%=j render(@cart) %>");
 
$('#current_item').css({'background-color':'#88ff88'}).
  animate({'background-color':'#114411'}, 1000);

Look at the app/helpers director

ls -p app
assets/
channels/
controllers/
helpers/
jobs/
mailers/
models/
views/
ls -p app/helpers
application_helper.rb
carts_helper.rb
line_items_helper.rb
products_helper.rb
store_helper.rb

Call a hidden_div_if helper

edit app/views/layouts/application.html.erb
        <% if @cart %>
          <%= hidden_div_if(@cart.line_items.empty?, id: 'cart') do %>
            <%= render @cart %>
          <% end %>
        <% end %>

Implement helper

edit app/helpers/application_helper.rb
module ApplicationHelper
  def hidden_div_if(condition, attributes = {}, &block)
    if condition
      attributes["style"] = "display: none"
    end
    content_tag("div", attributes, &block)
  end
end

Remove notice

edit app/controllers/carts_controller.rb
  def destroy
    @cart.destroy if @cart.id == session[:cart_id]
    session[:cart_id] = nil
    respond_to do |format|
      format.html { redirect_to store_index_url }
      format.json { head :no_content }
    end
  end

Demonstrate emptying and recreating the cart

get /carts/2

Your Cart

Rails, Angular, Postgres, and Bootstrap $90.00
Seven Mobile Apps in Seven Weeks $52.00
Total $142.00

Your Cart

Rails, Angular, Postgres, and Bootstrap $90.00
Seven Mobile Apps in Seven Weeks $52.00
Total $142.00
post /carts/2
You are being redirected.
get http://localhost:3000/

Your Pragmatic Catalog

Dcbang

Rails, Angular, Postgres, and Bootstrap

Powerful, Effective, and Efficient Full-Stack Web Development As a Rails developer, you care about user experience and performance, but you also want simple and maintainable code. Achieve all that by embracing the full stack of web development, from styling with Bootstrap, building an interactive user interface with AngularJS, to storing data quickly and reliably in PostgreSQL. Take a holistic view of full-stack development to create usable, high-performing applications, and learn to use these technologies effectively in a Ruby on Rails environment.

$45.00
Adrpo

Ruby Performance Optimization

Why Ruby Is Slow, and How to Fix It You don’t have to accept slow Ruby or Rails performance. In this comprehensive guide to Ruby optimization, you’ll learn how to write faster Ruby code—but that’s just the beginning. See exactly what makes Ruby and Rails code slow, and how to fix it. Alex Dymo will guide you through perils of memory and CPU optimization, profiling, measuring, performance testing, garbage collection, and tuning. You’ll find that all those “hard” things aren’t so difficult after all, and your code will run orders of magnitude faster.

$46.00
7apps

Seven Mobile Apps in Seven Weeks

Native Apps, Multiple Platforms Answer the question “Can we build this for ALL the devices?” with a resounding YES. This book will help you get there with a real-world introduction to seven platforms, whether you’re new to mobile or an experienced developer needing to expand your options. Plus, you’ll find out which cross-platform solution makes the most sense for your needs.

$26.00
get /

Your Pragmatic Catalog

Dcbang

Rails, Angular, Postgres, and Bootstrap

Powerful, Effective, and Efficient Full-Stack Web Development As a Rails developer, you care about user experience and performance, but you also want simple and maintainable code. Achieve all that by embracing the full stack of web development, from styling with Bootstrap, building an interactive user interface with AngularJS, to storing data quickly and reliably in PostgreSQL. Take a holistic view of full-stack development to create usable, high-performing applications, and learn to use these technologies effectively in a Ruby on Rails environment.

$45.00
Adrpo

Ruby Performance Optimization

Why Ruby Is Slow, and How to Fix It You don’t have to accept slow Ruby or Rails performance. In this comprehensive guide to Ruby optimization, you’ll learn how to write faster Ruby code—but that’s just the beginning. See exactly what makes Ruby and Rails code slow, and how to fix it. Alex Dymo will guide you through perils of memory and CPU optimization, profiling, measuring, performance testing, garbage collection, and tuning. You’ll find that all those “hard” things aren’t so difficult after all, and your code will run orders of magnitude faster.

$46.00
7apps

Seven Mobile Apps in Seven Weeks

Native Apps, Multiple Platforms Answer the question “Can we build this for ALL the devices?” with a resounding YES. This book will help you get there with a real-world introduction to seven platforms, whether you’re new to mobile or an experienced developer needing to expand your options. Plus, you’ll find out which cross-platform solution makes the most sense for your needs.

$26.00
post /line_items?product_id=2
You are being redirected.
get http://localhost:3000/

Your Cart

Rails, Angular, Postgres, and Bootstrap $45.00
Total $45.00

Your Pragmatic Catalog

Dcbang

Rails, Angular, Postgres, and Bootstrap

Powerful, Effective, and Efficient Full-Stack Web Development As a Rails developer, you care about user experience and performance, but you also want simple and maintainable code. Achieve all that by embracing the full stack of web development, from styling with Bootstrap, building an interactive user interface with AngularJS, to storing data quickly and reliably in PostgreSQL. Take a holistic view of full-stack development to create usable, high-performing applications, and learn to use these technologies effectively in a Ruby on Rails environment.

$45.00
Adrpo

Ruby Performance Optimization

Why Ruby Is Slow, and How to Fix It You don’t have to accept slow Ruby or Rails performance. In this comprehensive guide to Ruby optimization, you’ll learn how to write faster Ruby code—but that’s just the beginning. See exactly what makes Ruby and Rails code slow, and how to fix it. Alex Dymo will guide you through perils of memory and CPU optimization, profiling, measuring, performance testing, garbage collection, and tuning. You’ll find that all those “hard” things aren’t so difficult after all, and your code will run orders of magnitude faster.

$46.00
7apps

Seven Mobile Apps in Seven Weeks

Native Apps, Multiple Platforms Answer the question “Can we build this for ALL the devices?” with a resounding YES. This book will help you get there with a real-world introduction to seven platforms, whether you’re new to mobile or an experienced developer needing to expand your options. Plus, you’ll find out which cross-platform solution makes the most sense for your needs.

$26.00
rails test
Run options: --seed 1703
 
# Running:
 
...............................
 
Finished in 0.788195s, 39.3304 runs/s, 83.7356 assertions/s.
 
31 runs, 66 assertions, 0 failures, 0 errors, 0 skips

11.5 Iteration F5: Broadcasting Updates 11.3 Iteration F3: Highlighting Changes