ko.bindingHandlers.checkedForComplex.js

ko.bindingHandlers.checkedForComplex = {
    init: function(element, valueAccessor, allBindingsAccessor, viewModel) {
        ko.utils.registerEventHandler(element, 'click', function() {
            var observable = valueAccessor();
            observable(viewModel);
        });
    },

    update: function(element, valueAccessor, allBindingsAccessor, viewModel) {
        var value = ko.utils.unwrapObservable(valueAccessor());
        element.checked = value === viewModel;
    }
};