JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//knockoutjs.com/downloads/knockout-2.2.1.js"></script>
<div>
    <h1 data-bind="text: name"></h1>
    <ul data-bind="foreach: items">
        <li data-bind="text: value() + ': ' + name()"></li>
    </ul>
    
    <div>
        <strong>data.items.length == </strong>
        <span data-bind="text: items.length"></span>
        <span data-bind="text: 'Type of Items:' + typeof items"></span>
        <span data-bind="text: 'Is An array ?:' + Array.isArray(items)"></span>
    </div>
    <div>
        <strong>data.items().length == </strong>
        <span data-bind="text: items().length"></span>
        <span data-bind="text: 'Type of Items:' + typeof items()"></span>
        <span data-bind="text: 'Is An array ?:' + Array.isArray(items())"></span>
    </div>
</div>

JavaScript

var data = {
    name: ko.observable("Test"),
    items: ko.observableArray([
        { name: ko.observable("First Thing"), value: ko.observable(1) },
        { name: ko.observable("Second Thing"), value: ko.observable(2) },
        { name: ko.observable("Third Thing"), value: ko.observable(3) }
    ])
};

ko.applyBindings(data, document.getElementsByTagName("div")[0]);