Knockoutjs.com - Cart editor example

http://knockoutjs.com/examples/cartEditor.html

by bizamajig

HTML

<script src="http://knockoutjs.com/examples/resources/sampleProductCategories.js"></script>
<script src="http://github.com/downloads/SteveSanderson/knockout/knockout-2.1.0.js"></script>
<div class='liveExample'> 
    
    <table width='100%'>
        <thead>
            <tr>
                <th width='25%'>Category</th>
                <th width='25%'>Product</th>
                <th class='price' width='15%'>Price</th>
                <th class='quantity' width='10%'>Quantity</th>
                <th class='price' width='15%'>Subtotal</th>
                <th width='10%'> </th>
            </tr>
        </thead>
        <tbody data-bind='foreach: lines'>
            <tr>
                <td>
                    <select data-bind='options: sampleProductCategories, optionsText: "name", optionsCaption: "Select...", value: category'> </select>
                </td>
                <td data-bind="with: category">
                    <select data-bind='options: products, optionsText: "name", optionsCaption: "Select...", value: $parent.product'> </select>
                </td>
                <td class='price' data-bind='with: product'>
                    <span data-bind='text: formatCurrency(price)'> </span>
                </td>
                <td class='quantity'>
                    <input data-bind='visible: product, value: quantity, valueUpdate: "afterkeydown"' />
                </td>
                <td class='price'>
                    <span data-bind='visible: product, text: formatCurrency(subtotal())' > </span>
                </td>
                <td>
                    <a href='#' data-bind='click: $parent.removeLine'>Remove</a>
                </td>
            </tr>
        </tbody>
    </table>
    <p class='grandTotal'>
        Total value: <span data-bind='text: formatCurrency(grandTotal())'> </span>
    </p>
    <button data-bind='click: addLine'>Add product</button>
    <button data-bind='click: save'>Submit order</button>
    
</div>

CSS

body { font-family: arial; font-size: 14px; }

.liveExample { padding: 1em; background-color: #EEEEDD; border: 1px solid #CCC; max-width: 655px; }
.liveExample input { font-family: Arial; }
.liveExample b { font-weight: bold; }
.liveExample p { margin-top: 0.9em; margin-bottom: 0.9em; }
.liveExample select[multiple] { width: 100%; height: 8em; }
.liveExample h2 { margin-top: 0.4em; font-weight: bold; font-size: 1.2em; }

.liveExample th { text-align: left; font-weight: bold; }
.liveExample .price { text-align: right; padding-right: 2em; }
.liveExample .grandTotal { border-top: 1px solid silver; padding-top: 0.5em; font-size: 1.2em; }
.liveExample .grandTotal SPAN { font-weight: bold; }

.liveExample table, .liveExample td, .liveExample th { padding: 0.2em; border-width: 0; margin: 0; vertical-align: top; }
.liveExample td input, .liveExample td select { width: 8em; }
.liveExample td.quantity input { width: 4em; }
.liveExample td select { height: 1.8em; white-space: nowrap; }


li { list-style-type: disc; margin-left: 20px; }

JavaScript

function formatCurrency(value) {
    return "$" + value.toFixed(2);
}
 
var CartLine = function() {
    var self = this;
    self.category = ko.observable();
    self.product = ko.observable();
    self.quantity = ko.observable(1);
    self.subtotal = ko.computed(function() {
        return self.product() ? self.product().price * parseInt("0" + self.quantity(), 10) : 0;
    });
 
    // Whenever the category changes, reset the product selection
    self.category.subscribe(function() {
        self.product(undefined);
    });
};
 
var Cart = function() {
    // Stores an array of lines, and from these, can work out the grandTotal
    var self = this;
    self.lines = ko.observableArray([new CartLine()]); // Put one line in by default
    self.grandTotal = ko.computed(function() {
        var total = 0;
        $.each(self.lines(), function() { total += this.subtotal() })
        return total;
    });
 
    // Operations
    self.addLine = function() { self.lines.push(new CartLine()) };
    self.removeLine = function(line) { self.lines.remove(line) };
    self.save = function() {
        var dataToSave = $.map(self.lines(), function(line) {
            return line.product() ? {
                productName: line.product().name,
                quantity: line.quantity()
            } : undefined
        });
        alert("Could now send this to server: " + JSON.stringify(dataToSave));
    };
};
 
ko.applyBindings(new Cart());