(function bfs() {
  var root = document.querySelectorAll(':root');
  let queue = [root];
  let count = 0;
  while(queue.length){
    let domList = queue.pop();
    domList.length && (count+= domList.length);
    if(domList && domList.length){
      for(let i=0;i<domList.length;i++){
        queue.push(domList[i].childNodes);
      }
    }
  }
  console.log(count);
})();