JSFiddle - React, Tailwind, and code Playground

HTML

<a class="thing">With <strong>strong</strong> stuff</a>

JavaScript

const changeTagName = (element, newTagName) => {
  // Create a replacement tag of the desired type
  var replacement = document.createElement(newTagName);
  Array.from(element.attributes).forEach(attribute => {
    replacement.setAttribute(attribute.nodeName, attribute.nodeValue);
  });
  replacement.innerHTML = element.innerHTML;
  element.parentNode.replaceChild(replacement, element);
}

const a = document.getElementsByTagName('a')[0]
changeTagName(a, 'span')