JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" data-bind="value: someText, customBinding: {some: 'Shrikrishna'}">

JavaScript

ko.bindingHandlers.customBinding = {
	update: function(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
     
    		var value = ko.isObservable(valueAccessor()) ? valueAccessor() : valueAccessor

        console.log( JSON.stringify(value) );
               alert( JSON.stringify(value) );
    }
}

ko.applyBindings({
    someText: ko.observable("inital value")
});