JSFiddle - React, Tailwind, and code Playground

HTML

<button type="button" id="b1" data-index="0">B1</button>
<button type="button" id="b2" data-index="1">B2</button>
<button type="button" id="b3" data-index="2">B3</button>
<button type="button" id="b4" data-index="3">B4</button>

JavaScript

$("button").click(function(event){
   alert($(event.currentTarget).attr("data-index"));
});