JS 组装无限级树

function lists(parentId, list) {
  let data = [];
  for (const key in list) {
    if (list[key].parent_id === parentId) {
      let child = this.lists(list[key].id, list);
      if (child.length > 0) {
        list[key].child = child;
      }
      data.push(list[key]);
    }
  }
  return data;
}