JSFiddle - React, Tailwind, and code Playground

HTML

<p>Send me spam: <input type="checkbox" data-bind="checked: wantsSpam" /></p>
<div data-bind="visible: wantsSpam">
    Preferred flavors of spam:
    <div><input type="checkbox" value="cherry" data-bind="checked: spamFlavors" /> Cherry</div>
    <div><input type="checkbox" value="almond" data-bind="checked: spamFlavors" /> Almond</div>
    <div><input type="checkbox" value="msg" data-bind="checked: spamFlavors" /> Monosodium Glutamate</div>
</div>

JavaScript

var viewModel = {
        wantsSpam: ko.observable(true),
        spamFlavors: ko.observableArray(["cherry","almond"]) 
    };
 
    
    viewModel.spamFlavors.push("msg");