JSFiddle - React, Tailwind, and code Playground

HTML

<input data-bind="value: someDate" type="date" ></input>
<br />
<input data-bind="value: dateString" type="date"></input>

JavaScript

var viewModel = {
    someDate: new Date(parseInt("/Date(1367708400000)/".substr(6))).toISOString().substr(0,10),
    dateString: ko.observable('2002-02-02')
};
console.log(viewModel.someDate);
console.log(viewModel.dateString());
ko.applyBindings(viewModel);