JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://rawgithub.com/Knockout-Contrib/Knockout-Validation/master/Dist/knockout.validation.min.js"></script>
<input type="text" data-bind="value: firstName"/>

JavaScript

//ko.validation.init();
var viewModel = {
    firstName: ko.observable().extend({
        minLength: { params: 3, message: "Please enter Valid number" }
        , maxLength: 10
    }),
}
ko.applyBindings(viewModel);