Sum of nested object values in Array using JavaScript

Javascript Web Development Object Oriented Programming

Following is the code to sum nested object values in array using JavaScript −

Example

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
   body {
      font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
   }
   .result {
      font-size: 18px;
      font-weight: 500;
      color: rebeccapurple;
   }
</style>
</head>
<body>
<h1>Sum of nested object values in Array</h1>
<div class="result"></div>
<button class="Btn">CLICK HERE</button>
<h3>
Click on the above button to sum the nested object values of json array
</h3>
<script>
   let json = {
      storeData: [
      {
         items: [
         {
            itemID: 12,
            cost: {
               costNum: 100,
            },
         },
         {
            itemID: 22,
            cost: {
               costNum: 250,
            },
         },
         {
            itemID: 19,
            cost: {
               costNum: 350,
            },
         },
      ],
   },
],
};
let resEle = document.querySelector(".result");
document.querySelector(".Btn").addEventListener("click", () => {
   let sum = 0;
   json.storeData.map((ele) => ({
      itemPrice: ele.items.forEach((item) => {
         sum += item.cost.costNum;
      }),
   }));
   resEle.innerHTML += "Total CostNum = " + sum + "<br>";
   });
</script>
</body>
</html>