JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://raw.github.com/timrwood/moment/2.0.0/min/moment.min.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/knockout/2.2.1/knockout-min.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/knockout.mapping/2.3.5/knockout.mapping.js"></script>
<strong>Text binding:</strong> <span data-bind="text: DueDate"></span>
<br /><br />
<strong>Custom binding:</strong> <span data-bind="textualDate: DueDate"></span>
<br /><br />
<input data-bind="value: DueDate" />

JavaScript

ko.bindingHandlers.textualDate = {
    update: function(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
        var valueUnwrapped = ko.utils.unwrapObservable(valueAccessor());
        var textContent = moment(valueUnwrapped).format("MMM Do YY");
        ko.bindingHandlers.text.update(element, function() { return textContent; });
    }
};

// Here is my json formatted date
var data = { "DueDate": Date(1362124800000) };
var vm = ko.mapping.fromJS(data);
ko.applyBindings(vm);