Duffer Derek

import hasClass from './hasClass';
/**
 * 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);
}