dist/es5/dev/templating/dom.js
function addClass(node, className) {
            if (node && node.el) {
                node.el.classList.add(className);
            }
        }
function addClass(node, className) {
            if (node && node.el) {
                node.el.classList.add(className);
            }
        }
Adding class in to node  @method addClass @param {dom.Element} node @param {String} className