不用递归生成无限层级的树

[
    {
      "id": 1,
      "name": "中华人民共和国",
      "parentId": 0,
    },
    {
      "id": 1001,
      "name": "浙江省",
      "parentId": 1,
    },
    {
      "id": 2001,
      "name": "杭州市",
      "parentId": 1001,
    },
    {
      "id": 3001,
      "name": "西湖区",
      "parentId": 2001,
    },
    {
      "id": 4001,
      "name": "杭州市第一人民医院",
      "parentId": 3001,
    },
    // 其他略
]

// 略，网上一抓一把

const buildTree = (itemArray, { id = 'id', parentId = 'parentId', children = 'children', topLevelId = '0' } = {}) => {
  return itemArray.filter((item) => {
    // 挂载子级
    item[children] = itemArray.filter((child) => String(item[id]) === String(child[parentId]));
    // 返回顶层数据
    return String(item[parentId]) === topLevelId;
  });
};

import { groupBy } from 'lodash';

const buildTree = (itemArray, { id = 'id', parentId = 'parentId', children = 'children', topLevelId = '0' } = {}) => {
  const parentObj = groupBy(itemArray, parentId)
  return itemArray.filter((item) => {
    // 挂载子级
    item[children] = parentObj[item[id]];
    // 返回顶层数据
    return String(item[parentId]) === topLevelId;
  });
};

const buildTree = (itemArray, { id = 'id', parentId = 'parentId', children = 'children', topLevelId = '0' } = {}) => {
  const parentMap = new Map(); // 临时存储所有父级
  const topLevelResult = [];   // 存储顶层结果
  for(let item of itemArray) {
    if(!parentMap.has(item[id])) {
      item[children] = []
    } else {
      item[children] = parentMap.get(item[id])[children];
    }

    parentMap.set(item.id, item)

    if(!parentMap.has(item[parentId])) {
      parentMap.set(item[parentId], {
        [children]: []
      });
    }
    parentMap.get(item[parentId])[children].push(item)
    if (String(item[parentId]) === String(topLevelId)) {
      topLevelResult.push(item)
    }
  }
  return topLevelResult;
}