use encapsulated quantityDiscount getter at Order.price

Author: kaiosilveira

order.js

@@ -21,9 +21,7 @@ class Order {
 
   get price() {
     return (
-      this.basePrice -
-      Math.max(0, this.quantity - 500) * this.itemPrice * 0.05 +
-      Math.min(this.quantity * this.itemPrice * 0.1, 100)
+      this.basePrice - this.quantityDiscount + Math.min(this.quantity * this.itemPrice * 0.1, 100)
     );
   }
 }