Unable to parse bindings knockout error

Question

I am working with knockout and have run in to a problem I dont know how to fix. I retrieve a json object back from an asp.net mvc controller. I pass it to the following function:

load = function (data) {
        var myViewModel = function () {
            var self = this;

            ko.mapping.fromJS(data, self);

            self.hasItems = ko.computed(function () {
                return self.NumberOfItems > 0;
            }, self);

        };
        ko.applyBindings(myViewModel, window.document.getElementById("my-container"));
    }

I am adding custom behaviour to my model object based upon what is returned in the json, in particular the NumberOfItems property of the json. My markup is:

 <div class="content" style="display: none;" data-bind="visible: hasItems === false">
    <span class="empty">My Items</span>
</div>

But I keep getting this error:

Error: Unable to parse bindings. Message: ReferenceError: hasItems is not defined; Bindings value: visible: hasItems === false

I have no idea why - I am a newbie to this so really appreciate any help?

Answer 1

applyBindings expects an object. Try

ko.applyBindings(new myViewModel(), window.document.getElementById("my-container"));

Also, when you want to get the value of an observable, you'll need to use parentheses.

return self.NumberOfItems() > 0;

http://jsfiddle.net/36xtR/