prepared to applly chain

src/chain-of-responsability/discounts-calculator/Budget.ts

@@ -17,4 +17,14 @@ export default class Budget {
 
     return nItems;
   }
+
+  getTotal(): number {
+    return this.items
+      .map((product: Product) => {
+        return product.price;
+      })
+      .reduce((prev: number, current: number) => {
+        return prev + current;
+      }, 0);
+  }
 }

src/chain-of-responsability/discounts-calculator/Calculator.ts

@@ -0,0 +1,20 @@
+import Budget from "./Budget";
+
+export default class Calculator {
+  constructor(private budged: Budget) {}
+
+  calculate(): number {
+    const total: number = this.budged.getTotal();
+    let discount = 0;
+    // discount more than 2 items
+    if (this.budged.getItems().length > 2) {
+      discount += total * 0.1;
+    }
+
+    if (total > 500) {
+      discount += total * 0.07;
+    }
+
+    return total - discount;
+  }
+}

src/chain-of-responsability/discounts-calculator/index.ts

@@ -1,4 +1,5 @@
 import Budged from "./Budget";
+import Calculator from "./Calculator";
 
 const budget = new Budged();
 
@@ -7,4 +8,6 @@ budget
   .add({ code: "B335", name: "Monitor LG Ultrawide 29", price: 1500.0 })
   .add({ code: "V887", name: "Suporte Monitor Top", price: 300.0 });
 
-
+const calculator = new Calculator(budget);
+
+console.log(calculator.calculate())