// 递归算法
export const initTree = (arr, parentId='0',id) => {
    const tree = [];
    arr.filter(item => item.parentId === parentId).forEach(item => {
      const children = initTree(arr, item[id]);
      if (children.length > 0) {
        item.children = children;
      }
      tree.push(item);
    });
    return tree;
}