code: function renderAttrs (node) {
    var attrs = node.data.attrs;
    var res = '';
  
    var parent = node.parent;
    while (isDef(parent)) {
      if (isDef(parent.data) && isDef(parent.data.attrs)) {
        attrs = Object.assign({}, attrs, parent.data.attrs);
      }
      parent = parent.parent;
    }
  
    if (isUndef(attrs)) {
      return res
    }
  
    for (var key in attrs) {
      if (key === 'style') {
        // leave it to the style module
        continue
      }
      res += renderAttr(key, attrs[key]);
    }
    return res
  }
docs: /*