JSFiddle - React, Tailwind, and code Playground

HTML

<button type = "button" class = "btn btn-default"  data-id = "21"  id= "clickB"> Кнопка 1 </button>
<button type = "button" class = "btn btn-default"  id = "clickC">Кнопка 2 </button>

JavaScript

$('#clickC').click(function(){
	alert($('#clickB').data('id'));
});