code: function (elm, selector) {
          var i;
  
          // If it isn't an array then try to do some simple selectors instead of Sizzle for to boost performance
          if (elm.length === undefined) {
            // Simple all selector
            if (selector === '*') {
              return elm.nodeType == 1;
            }
  
            // Simple selector just elements
            if (simpleSelectorRe.test(selector)) {
              selector = selector.toLowerCase().split(/,/);
              elm = elm.nodeName.toLowerCase();
  
              for (i = selector.length - 1; i >= 0; i--) {
                if (selector[i] == elm) {
                  return true;
                }
              }
  
              return false;
            }
          }
  
          // Is non element
          if (elm.nodeType && elm.nodeType != 1) {
            return false;
          }
  
          var elms = elm.nodeType ? [elm] : elm;
  
          /*eslint new-cap:0 */
          return Sizzle(selector, elms[0].ownerDocument || elms[0], null, elms).length > 0;
        }
docs: Returns true/false if the specified element matches the specified css pattern.
  
  @method is
  @param {Node/NodeList} elm DOM node to match or an array of nodes to match.
  @param {String} selector CSS pattern to match the element against.