Knockoutjs.com - Cart Editor example

Fiddle for playing around with http://knockoutjs.com/examples/cartEditor.html

by Matt Diebolt

HTML

<script src="http://knockoutjs.com/examples/resources/sampleProductCategories.js"></script>
<script src="http://knockoutjs.com/downloads/knockout-2.0.0.debug.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' />
            </td>
            <td data-bind="if: category">
                <select data-bind='options: category().products, optionsText: "name", optionsCaption: "Select...", value: product' />
            </td>
            <td class='price' data-bind="with: product">
                <span data-bind='text: formatCurrency(price)' />
            </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())' />
            </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; margin: auto; }
.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() {
    this.category = ko.observable();
    this.product = ko.observable();
    this.quantity = ko.observable(1);
    this.subtotal = ko.computed(function() {
        return this.product() ? this.product().price * parseInt("0" + this.quantity(), 10) : 0;
    }, this);
 
    // Whenever the category changes, reset the product selection
    this.category.subscribe(function() {
        this.product(undefined);
    }, this);
};
 
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());