JSFiddle - React, Tailwind, and code Playground

JavaScript

var books = [
    {
    id: "easyreader",
    name: "easy reader",
    price: 4.95,
    discount: 0.10},
{
    id: "diaryofwimpykid",
    name: "diary of a wimpy kid",
    price: 6.95,
    discount: 0.10},
{
    id: "lucid",
    name: "lucid",
    price: 14.95,
    discount: 0.15},
{
    id: "frederickdouglas",
    name: "frederick douglas",
    price: 25.95,
    discount: 0.20}
];

function OrderBook() {
    var total = 0;

    bookname = prompt("Enter the name of the book that you want");
    qty = prompt("Enter the no. of books that you want");

    for (i = 0; i < books.length; i++) {
        if (bookname == books[i].name) {
            cost_of_order = (qty * books[i].price);
            totaldiscountprice = (qty * books[i].price) * books[i].discount;
            total = (qty * books[i].price) - totaldiscountprice;

            document.write("The cost of buying <b>" + qty + "</b> of <b>" + books[i].name + "</b> is <b>$" + cost_of_order.toFixed(2) + "</b><br/>");
            document.write("The discount for this purchase is <b>$" + totaldiscountprice.toFixed(2) + "</b><br/>");
            document.write("With discount, your total order cost is <b>$" + total.toFixed(2) + "</b><br/>");

            break;
        }
    }
    if (i == books.length) {
        alert("Sorry, " + user_name + " You entered an invalid product.  We will not include this in your order.");
    }

    if (confirm("Would you like to order another book?")) {
        total += OrderBook();
    }

    return total;
}



var user_name = "";
user_name = prompt("Welcome to Children's Nook Books. Please enter your name ", " ");

var sentence = "Hello " + user_name + " Please look through our available products and services before placing your order.";

alert(sentence);

var total_cost = 0;
total_cost += OrderBook();

document.write("<br/>With discount, your grand total is <b>$" + total_cost.toFixed(2) + "</b>");