How to write an function for traversing through a list in typescript?

I have the following output which needs to be parsed and have to calculate the total in order to display it on the front end in angular 7:-

{
    "cart": [
        {
            "id": 28,
            "Name": "Retin a gel",
            "Price": 50,
            "Quantity": 3,
            "Cost": 150,
            "createdAt": "2019-03-15 02:44:55.047 +00:00",
            "updatedAt": "2019-03-15 02:45:04.574 +00:00"
        }
    ]
}

in want to parse through this output and calculate total which sum of all total cost in typescript as a function to display it on the front end ? can some tell me how design such function?

You can reduce with destructuring like so:

let totalSum = yourObject.cart.reduce((acc, { Cost }) => acc + Cost, 0);

You can do like this,I hope it helps

let total = 0;
let JsonRes= "{
"cart": [
    {
        "id": 28,
        "Name": "Retin a gel",
        "Price": 50,
        "Quantity": 3,
        "Cost": 150,
        "createdAt": "2019-03-15 02:44:55.047 +00:00",
        "updatedAt": "2019-03-15 02:45:04.574 +00:00"
    }
   ]
 }"

for (let i = 0; i < JsonRes.cart.length(); i++) {
      total  + = +JsonRes.cart[i].Cost; 
}
console.log(total);