at it is performing service injection.
There are two ways to use this decorator.
You can either invoke it with no arguments, or you can pass it the registered name of the service.
When no arguments are passed, the service is loaded based on the name of the decorated property.
You can load the shopping cart service with no arguments like below.</p>
<div class="filename javascript"><div class="ribbon"></div><span>app/components/cart-contents.js</span><pre class="language-javascript line-numbers"><code class="