JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-1.11.0.min.js"></script>
<div id="koRoot">
    <div data-bind='"style": { "backgroundColor": color }'>aa
        <div data-bind="someCustomBinding: myValue">bb</div>
        <input type='text' data-bind="value: color"/>
    </div>
</div>

JavaScript

(function () {
    if (typeof ko !== 'undefined') {
        ko.bindingHandlers.someCustomBinding = {
            init: function (element, valueAccessor, allBindingAccessor, viewModel, bindingContext) {
                alert(JSON.parse('{' + $(element).parent().data("bind") + '}').style.backgroundColor);
            }
        }
    }
})();
$(document).ready(function () {
    var ViewModel = {
        myValue: 1,
        alwaysFalse: false,
        color: ko.observable()
    }
    ko.applyBindings(ViewModel, document.getElementById("koRoot"));
});