Question

I’m trying to map some data (returned from a jQuery $.ajax call) to a view model, but for some reason the nested array is not mapped.

    <p>Name: <input data-bind="value: Name" /></p>
    <p>Age: <input data-bind="value: Age" /></p>
    <p>Friends: <span data-bind="text: Friends.length"></span></p>



    <script type="text/javascript">
        var viewModel = null;
        var data = { "Name": "Simon", "Age": "24", "Friends": [{ "Name": "Bill", "Age": "24" }, { "Name": "Peter", "Age": "21"}]};
        viewModel = ko.mapping.fromJS(data);
        ko.applyBindings(viewModel);
    </script>

In this simple example Simon has no friends…

Answer 1

mapping.fromJS converts arrays to observable arrays, so Friends is an observable array and to access its underlying javascript array you need to call it: Friends().length