JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0-beta1/jquery.min.js"></script>
<input type="text" data-type="inputFullName" />
<br>
<br>
<input type="text" data-type="inputEmail" />
<br>
<br>
<input type="text" data-type="inputPhone" />
<br>
<br>
<input type="checkbox" id="chkbox" />
<label>Check here</label>
<br>
<br>
<button id="button1" disabled>Click</button>

JavaScript

$('input').on('keyup change', function () {

$('#button1').prop('disabled', $('input[data-type="inputFullName"]').val() == '' || 
     $('input[data-type="inputEmail"]').val() == '' || 
     $('input[data-type="inputPhone"]').val() == '' ||      	!$('input[type="checkbox"]').is(':checked'))
});