shopping cart knockout

by Leonardo Trimarchi

HTML

<h2>Your selected policies (<span data-bind="text: seats().length"></span>)</h2>

<table>
    <thead><tr>
        <th>Policy Holder name</th><th>Policy Type</th><th>Value</th><th></th>
    </tr></thead>
    <tbody data-bind="foreach: seats">
        <tr>
            <td><input data-bind="value: name" /></td>
            <td><select data-bind="options: $root.availableMeals, value: meal, optionsText: 'mealName'"></select></td>
            <td data-bind="text: formattedPrice"></td>
            <td><a href="#" data-bind="click: $root.removeSeat">Remove</a></td>
        </tr>    
    </tbody>
</table>

<button data-bind="click: addSeat, enable: seats().length < 8">Add Policy for Redemption</button>

<h3 data-bind="visible: totalSurcharge() > 0">
    Total value of Redemption: $<span data-bind="text: totalSurcharge().toFixed(2)"></span>
</h3>

JavaScript

// Class to represent a row in the seat reservations grid
function SeatReservation(name, initialMeal) {
    var self = this;
    self.name = name;
    self.meal = ko.observable(initialMeal);

    self.formattedPrice = ko.computed(function() {
        var price = self.meal().price;
        return price ? "$" + price.toFixed(2) : "None";        
    });    
}

// Overall viewmodel for this screen, along with initial state
function ReservationsViewModel() {
    var self = this;

    // Non-editable catalog data - would come from the server
    self.availableMeals = [
        { mealName: "MEDICARE SUPPLEMENT", price: 58.95 },
        { mealName: "LIFE INSURANCE", price: 34.95 },
        { mealName: "ACCIDENTAL AMPUTATION", price: 290 },
        { mealName: "PICKLE SLICING", price: 300 }
    ];    

    // Editable data
    self.seats = ko.observableArray([
        new SeatReservation("Johnny Knoxville", self.availableMeals[0]),
        new SeatReservation("Evel Kneivel", self.availableMeals[0])
    ]);

    // Computed data
    self.totalSurcharge = ko.computed(function() {
       var total = 0;
       for (var i = 0; i < self.seats().length; i++)
           total += self.seats()[i].meal().price;
       return total;
    });    

    // Operations
    self.addSeat = function() {
        self.seats.push(new SeatReservation("", self.availableMeals[0]));
    }
    self.removeSeat = function(seat) { self.seats.remove(seat) }
}

ko.applyBindings(new ReservationsViewModel());