Question

I’m getting duplicate values in JSON. I want to replace the previous value with new a value.

var obj = {};
obj.Product_Id = product_id;
obj.Qty = j;
var arr = [];
arr.push(obj);
var json = JSON.stringify(arr);

output is [{“Product_id”:1,”Qty”:1},{“Product_id”:2,”Qty”:1},{“Product_id”:1,”Qty”:2}]

i want this to be [{“Product_id”:1,”Qty”:2},{“Product_id”:2,”Qty”:1}]

If key repeat its value it should replace previous one not add the duplicate value

Answer 1

If you want to maintain a unique key, you must remove any existing element with this key and then add the new object

var arr = ...;
var newObj = ...;
arr = arr.filter(function(el) { return el.Product_id != newObj.Product_id; });
arr.push(newObj);

If you want to maintain the order and know an element with this key exists already, you can use map

var arr = ...;
var newObj = ...;
arr = arr.map(function(el) {
    if (el.Product_id != newObj.Product_id)
        return el;

    return newObj;
});

For a reference on Array methods and properties, you can look at Array.