Add code to check the answer and respond to the user

assets/js/script.js

@@ -7,7 +7,7 @@ document.addEventListener("DOMContentLoaded", function () {
     for (let button of buttons) {
         button.addEventListener("click", function () {
             if (this.getAttribute("data-type") === "submit") {
-                alert("You clicked Submit!");
+                checkAnswer();
             } else {
                 let gameType = this.getAttribute("data-type");
                 runGame(gameType);
@@ -36,11 +36,40 @@ function runGame(gameType) {
     }
 }
 
+/**
+ * Checks the answer against the first element in
+ * the returned calculateCorrectAnswer array
+ */
+
 function checkAnswer() {
+    let userAnswer = parseInt(document.getElementById("answer-box").value);
+    let calculatedAnswer = calculateCorrectAnswer();
+    let isCorrect = userAnswer === calculatedAnswer[0];
+
+    if (isCorrect) {
+        alert("Hey! You got it right! :D");
+    } else {
+        alert(`Awwww.... you answered ${userAnswer}. The correct answer was ${calculatedAnswer[0]}!`);
+    }
 
 }
 
+/**
+ * Gets the operands (the numbers) and the operator (plus, minus etc)
+ * directly from the dom, and returns the correct answer.
+ */
+
 function calculateCorrectAnswer() {
+    let operand1 = parseInt(document.getElementById('operand1').innerText);
+    let operand2 = parseInt(document.getElementById('operand2').innerText);
+    let operator = document.getElementById("operator").innerText;
+
+    if (operator === "+") {
+        return [operand1 + operand2, "addition"];
+    } else {
+        alert(`Unimplemented operator ${operator}`);
+        throw `Unimplemented operator ${operator}`;
+    }
 
 }