code: function mergeClassNames(from, to) {
      const classNames = from.classList;
      for (let i = 0; i < classNames.length; i++) {
          to.addClass(classNames[i]);
      }
  
      return to;
  }
docs: Adds class names from first node to second one
  @param  {Node} from
  @param  {Node} to
  @return {Node}