JSFiddle - React, Tailwind, and code Playground

HTML

<div data-simple="works"
data-no-numbers="works"
data-numbers-at-end-123="works"
data-numbers-123-in-middle="breaks"
data-12-numbers-first="breaks"></div>

<p></p>

JavaScript

var div = $('div');
var p = $('p');
var keys = [];
$.each(div.data(), function (key, val) {
    keys.push(key);
});
p.text(keys.join(', '));