vue 中使用querySelect 封装的万能选择器

function query (el) {
  if (typeof el === 'string') {
    var selector = el;
    el = document.querySelector(el);
    if (!el) {
      "development" !== 'production' && warn(
        'Cannot find element: ' + selector
      );
      return document.createElement('div')
    }
  }
  return el
}