function.js

const items = [
    {name: "Item 1", price: 20, in_stock: true},
    {name: "Item 2", price: 40, in_stock: true},
    {name: "Item 3", price: 40, in_stock: false},
];

function inStockItems(items) {
    const inStockItems = [];
    for (let i = 0; i < items.length; i++) {
        if (items[i].in_stock) 
            inStockItems.push(items[i]);
    }
    return inStockItems;
}

function total(items) {
    let total = 0;
    for (let i = 0; i < items.length; i++) {
        total += items[i].price;
    }
    return total;
}


console.log(total(inStockItems(items)));