JSFiddle - React, Tailwind, and code Playground

HTML

<span>Test</span>

CSS

span {
  font-family: Verdana;
  font-size: 16px;
  font-weight: bold;
  line-height: 1.15;
}

JavaScript

document.querySelectorAll("span").forEach(el => {
  el.textContent = el.offsetHeight + "px";
});