JSFiddle - React, Tailwind, and code Playground

HTML

<button id="btn-1" data-mydata="Hello">First Button</button>
<button id="btn-2" data-mydata="World">Second Button</button>
<button id="btn-3" data-mydata="!">Third Button</button>

JavaScript

var btn1 = document.getElementById('btn-1');
var btn2 = document.getElementById('btn-2');
var btn3 = document.getElementById('btn-3');
var btns = [btn1, btn2, btn3];

function getBtnId(btn) {
 btn.addEventListener('click', function() {
 	alert(this.id + "\n" + this.dataset.mydata);
 });
}

btns.forEach(getBtnId);