JSFiddle - React, Tailwind, and code Playground
HTML
<div dir="ltr" id="foo">bar</div>
<div style="direction:ltr" id="baz">quux</div>
<div dir="ltr"><div id="jeez">whiz</div></div>
JavaScript
Array.prototype.forEach.call(document.querySelectorAll('#foo, #baz, #jeez'), function (elem) {
console.log(getComputedStyle(elem).direction);
});