I am really new to javascript so forgive any mistakes in my presentation of my question. I have the following object and am trying to figure out how to find the sum quantity of all items. I am looking for the output of "17".

Here is the object:

const cart = {
    "tax": .10,
    "items": [
        {
            "title": "milk",
            "price": 4.99,
            "quantity": 2
        },
        {
            "title": "rice",
            "price": 0.99,
            "quantity": 2
        },
        {
            "title": "candy",
            "price": 0.99,
            "quantity": 3
        },
        {
            "title": "bread",
            "price": 2.99,
            "quantity": 1
        },
        {
            "title": "apples",
            "price": 0.75,
            "quantity": 9
        }
    ]
}

I have been working on finding solutions for the last 4 hours. This includes trying to find videos/written info on how to understand objects/arrays that are nested within properties. Any help in getting pointed in the right direction would be greatly appreciated. Thank you.

CodePudding user response：

Loop through the "items" array and add all the quantities:

let sum = 0;
for(let i = 0; i < cart.items.length; i  ){
     sum  = cart.items[i].quantity;
}

console.log(sum) // Should be 17.

CodePudding user response：

You have to use below code with best practices.

const cart = {
"tax": .10,
"items": [
    {
        "title": "milk",
        "price": 4.99,
        "quantity": 2
    },
    {
        "title": "rice",
        "price": 0.99,
        "quantity": 2
    },
    {
        "title": "candy",
        "price": 0.99,
        "quantity": 3
    },
    {
        "title": "bread",
        "price": 2.99,
        "quantity": 1
    },
    {
        "title": "apples",
        "price": 0.75,
        "quantity": 9
    }
]};

let items = cart.items;
let sum = 0;
items.forEach(function(item){
    sum  = item.quantity
});
console.log(sum)