how to merge duplicate value in array of object site:stackoverflow.com
var myArray = [
{productId: 116605, productserialno: "324234"},
{productId: 106290, productserialno: "12121"},
{productId: 106290, productserialno: "12121"},
{productId: 106293, productserialno: "4324343"}
];
var grouped = myArray.reduce(function (obj, product) {
obj[product.productId] = obj[product.productId] || [];
obj[product.productId].push(product.productserialno);
return obj;
}, {});
var groups = Object.keys(grouped).map(function (key) {
return {product: key, productserialno: grouped[key]};
});
var pre = document.createElement("pre");
pre.innerHTML = JSON.stringify(groups, null, 4);
document.body.appendChild(pre);