JSFiddle - React, Tailwind, and code Playground

HTML

<div
data-simple="works"
data-full-words="works"
data-single-letter-at-end-i="works"
data-i-single-letter-at-beginning="works"
data-single-letter-i-in-middle="breaks"
data-two-single-letters-i-and-d-in-middle="breaks"
data-more-full-words="works"
></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(', '));