dom-helpers/esm/addClass.js

tiny modular DOM lib for ie9+

import hasClass from "./hasClass.js";

/**
 * Adds a CSS class to a given element.
 *
 * @param element the element
 * @param className the CSS class name
 */
export default function addClass(element, className) {
  if (element.classList) element.classList.add(className);else if (!hasClass(element, className)) if (typeof element.className === 'string') element.className = `${element.className} ${className}`;else element.setAttribute('class', `${element.className && element.className.baseVal || ''} ${className}`);
}