Search⌘ K
AI Features
Home
Courses
Agile Web Development Using Rails 6

Hiding an Empty Cart with a Custom Helper

Explore how to implement a custom helper method in Rails to conditionally render the shopping cart only when it has items. Understand the benefits of abstracting view logic into helpers, managing flash messages with JavaScript, and enhancing responsiveness using Ajax to create a cleaner and more dynamic e-commerce interface.

We'll cover the following...

Hiding empty cart

The customer has one last request. Right now, even carts with nothing in them are displayed in the sidebar. Can we arrange for the cart to appear only when it has some content? But of course!

In fact, we have a number of options. The simplest is to include the HTML for the cart only if the cart has something in it. We can do this completely within the _cart partial:

HTML
<% unless cart.line_items.empty? %> 
<h2>Your Cart</h2>
<table>
  <%= render(cart.line_items) %>
  <tr class="total_line">
    <td colspan="2">Total</td>
    <td class="total_cell"><%= number_to_currency(cart.total_price) %></td>
  </tr>
</table>
<%= button_to 'Empty cart', cart, method: :delete, confirm: 'Are you sure?' %>
<% end %>

Although this works, the code is a bit odd. Our application layout is rendering a cart partial, which then turns around and avoids rendering anything if the cart is empty. It would be cleaner if the application layout had the logic for rendering the cart only when needed, while the cart partially continues to just render when asked. While we could do this with a similar unless statement ...