Question

Okay, I have an issue using Knockout in that it isn’t able to parse a click binding on a child element of an observable array. I suspect that I’m having an issue with my mapping, but I can’t figure it out. I have a jsFiddle that I created:

http://jsfiddle.net/internetH3ro/ShjeE/1/

Here’s my JS:

var PaycheckBudgetItem = function(data) {
    var self = this;
    self.PaycheckBudgetItemId = ko.observable(data.PaycheckBudgetItemId);
    self.PaycheckBudgetId = ko.observable(data.PaycheckBudgetId);
    self.Description = ko.observable(data.Description);
    self.Amount = ko.observable(data.Amount);
    self.DueDate = ko.observable(data.DueDate);
    self.IsPaid = ko.observable(data.IsPaid);
    self.PaidStatus = ko.observable(data.PaidStatus);

    self.updateStatus = function() {
        alert('test');
    };
};

var mapping = {
    'Items': {
        create: function(options) {
            return new PaycheckBudgetItem(options.data);
        }
    }
};

var PaycheckBudget = function(data) {
    var self = this;
    self.PaycheckBudgetId = ko.observable(data.PaycheckBudgetId);
    self.PaycheckBudgetDate = ko.observable(data.PaycheckBudgetDate);
    self.PaycheckBudgetAmount = ko.observable(data.PaycheckBudgetAmount);
    self.Remaining = ko.observable(data.Remaining);
    self.Items = ko.observableArray(data.Items);
    ko.mapping.fromJSON(data.Items, mapping, self.Items);
};

var BudgetListViewModel = function(data) {
    var self = this;
    self.budgets = ko.observableArray(data);
};

var data = [
    {
    "PaycheckBudgetId": 1,
    "PaycheckBudgetDate": "11/9/2012",
    "PaycheckBudgetAmount": 2315,
    "Items": [
        {
        "PaycheckBudgetItemId": 11,
        "PaycheckBudgetId": 1,
        "Description": "Rent",
        "Amount": 400,
        "DueDate": "11/9/2012",
        "IsPaid": "Unpaid",
        "PaidStatus": false},
    {
        "PaycheckBudgetItemId": 12,
        "PaycheckBudgetId": 1,
        "Description": "Cell Phone",
        "Amount": 166,
        "DueDate": "11/9/2012",
        "IsPaid": "Unpaid",
        "PaidStatus": false}
    ],
    "Remaining": 1749},
{
    "PaycheckBudgetId": 2,
    "PaycheckBudgetDate": "11/23/2012",
    "PaycheckBudgetAmount": 2315,
    "Items": [
        {
        "PaycheckBudgetItemId": 3,
        "PaycheckBudgetId": 2,
        "Description": "Rent",
        "Amount": 400,
        "DueDate": "11/23/2012",
        "IsPaid": "Unpaid",
        "PaidStatus": false},
    {
        "PaycheckBudgetItemId": 4,
        "PaycheckBudgetId": 2,
        "Description": "Tuition",
        "Amount": 250,
        "DueDate": "11/23/2012",
        "IsPaid": "Unpaid",
        "PaidStatus": false}
    ],
    "Remaining": 1665}
];

ko.applyBindings(new BudgetListViewModel(data), $('#budget-list-container')[0]);​

Here’s my HTML:

<div id="budget-list-container" class="well sidebar-nav">
        <ul class="nav nav-list" data-bind="template: { name: 'budgetTemplate', foreach: budgets, as: 'budget' }">
            <script type="text/html" id="budgetTemplate">
                <li class="nav-header">
                    Paycheck for <span data-bind="text: PaycheckBudgetDate"></span> - <span data-bind="text: formatCurrency(PaycheckBudgetAmount)"></span>
                </li>
                <li>
                    <table class="table table-bordered table-condensed">
                        <thead>
                            <tr>
                                <th>Description</th>
                                <th>Amount</th>
                                <th>Due Date</th>
                                <th>Paid/Unpaid</th>
                            </tr>
                        </thead>
                        <tbody data-bind="template: { name: 'budgetItemTemplate', foreach: Items, as: 'budgetItem' }"></tbody>
                    </table>
                        Remaining: <span data-bind="text: formatCurrency(Remaining)"></span>
                    <hr />
                </li>
            </script>
            <script type="text/html" id="budgetItemTemplate">
                <tr>
                    <td><span data-bind="text: Description"></span></td>
                    <td><span data-bind="text: formatCurrency(Amount)"></span></td>
                    <td><span data-bind="text: DueDate"></span></td>
                    <td>
                        <button class="btn-link pull-right update-status" data-bind="text: IsPaid, click: updateStatus" />
                    </td>
                </tr>
            </script>
        </ul>
    </div>​

The meat of it is this. I have 2 KO models, PaycheckBudget and PaycheckBudgetItem. PaycheckBudget contains an observable array of PaycheckBudgetItem models. There is a function on the PaycheckBudgetItem model named “updateStatus” that is bound to a click event in my HTML. When I load my page, I get the error “Unable to parse bindings. updateStatus is not defined”.

I’m assuming that my issue is somewhere in my mapping of items. If I remove the click handler, everything binds and displays properly.

If anyone could help me out, maybe point out what I’m missing, that would be super helpful. I’m somewhat new to the Knockout stuff, so it’s likely I’m missing something obvious/simple.

(And no, none of the data in my fiddle is sensitive or real-world, just dummy data. 🙂 )

Answer 1

I did answer your question in the KnockoutJs JabbR chat room.

You’re correct in your assumption. The problem seems to be mainly your mapping. You’re never even calling the constructor of the PaycheckBudget class. For example, your BudgetListViewModel constructor looks like:

var BudgetListViewModel = function(data) {
    var self = this;
    self.budgets = ko.observableArray(data);
};

But should probably be something like:

var BudgetListViewModel = function(data) {
    var self = this;
    self.budgets = ko.observableArray(ko.utils.arrayMap(data, function(item){
        return new PaycheckBudget(item);
    }));
};

II’ve edited your jsfiddle a little and have a working sample at: http://jsfiddle.net/KBpET/. I did edit the other mapping first, so I never checked if the item mapping is correct or not, but I’m sure you’ll be able to solve that step (the code for items has been changed in the fiddle linked).

Hope it helps!

/Robert