列表和树状数据互转

// 列表数据
[
    {
        id: 1,
        name: '节点1',
        // 0表示为顶级节点
        parentId: 0
    },
    {
        id: 2,
        name: '节点1-1',
        parentId: 1
    }
    ...
]
// 树状数据
[
    {
        id: 1,
        name: '节点1',
        parentId: 0,
        children: [
            {
                id:2,
                name: '节点1-1',
                parentId:1
            }
        ]
    }
]

const arr = [
  { id: 1, parentId: -1 },
  { id: 11, parentId: 1 },
  { id: 12, parentId: 1 },
  { id: 2, parentId: -1 },
  { id: 21, parentId: 2 },
  { id: 22, parentId: 2 },
  { id: 221, parentId: 22 },
];

列表转树状数据

function listToTree(data) {
  const temp = {};
  const treeData = [];
  for (let i = 0; i < data.length; i++) {
    temp[data[i].id] = data[i];
  }
  // eslint-disable-next-line no-restricted-syntax
  for (const i in temp) {
    // 假定-1为根id
    if (+temp[i].parentId !== -1) {
      if (!temp[temp[i].parentId].children) {
        temp[temp[i].parentId].children = [];
      }
      temp[temp[i].parentId].children.push(temp[i]);
    } else {
      treeData.push(temp[i]);
    }
  }
  return treeData;
}

树状数据转列表

function treeToList(data) {
  const res = [];
  const dfs = (tree, pid) => {
    tree.forEach((item) => {
      if (item.children) {
        dfs(item.children, item.id);
        delete item.children;
      }
      res.push({ ...item, pid });
    });
  };
  // 假定-1为根id
  dfs(data, -1);
  return res;
}