es6 tutorial

build/main.bundle.js

@@ -0,0 +1,17 @@
+'use strict';
+
+var calculateMonthlyPayment = function calculateMonthlyPayment(principal, years, rate) {
+    if (rate) {
+        var monthlyRate = rate / 100 / 12;
+    }
+    var monthlyPayment = principal * monthlyRate / (1 - Math.pow(1 / (1 + monthlyRate), years * 12));
+    return monthlyPayment;
+};
+
+document.getElementById('calcBtn').addEventListener('click', function () {
+    var principal = document.getElementById("principal").value;
+    var years = document.getElementById("years").value;
+    var rate = document.getElementById("rate").value;
+    var monthlyPayment = calculateMonthlyPayment(principal, years, rate);
+    document.getElementById("monthlyPayment").innerHTML = monthlyPayment.toFixed(2);
+});

index.html

@@ -30,6 +30,6 @@ <h1>Mortgage Calculator</h1>
     </div>
     <h2>Monthly Payment: <span id="monthlyPayment" class="currency"></span></h2>
 </div>
-<script src="js/main.js"></script>
+<script src="build/main.bundle.js"></script>
 </body>
 </html>