使用下划线js将平面JSON转换为嵌套

[
  {"id": 1, "name": "Alice", "parentId": null},
  {"id": 2, "name": "Bob", "parentId": 1},
  {"id": 3, "name": "Charlie", "parentId": 1},
  {"id": 4, "name": "David", "parentId": 2}
]

[
  {
    "id": 1,
    "name": "Alice",
    "children": [
      {
        "id": 2,
        "name": "Bob",
        "parentId": 1,
        "children": [
          {
            "id": 4,
            "name": "David",
            "parentId": 2,
            "children": []
          }
        ]
      },
      {
        "id": 3,
        "name": "Charlie",
        "parentId": 1,
        "children": []
      }
    ]
  }
]

const _ = require('underscore');

function buildTree(items) {
  const rootItems = [];
  const lookup = {};

  // 初始化lookup表
  _.each(items, item => {
    lookup[item.id] = { ...item, children: [] };
  });

  // 构建树结构
  _.each(items, item => {
    if (item.parentId !== null) {
      lookup[item.parentId].children.push(lookup[item.id]);
    } else {
      rootItems.push(lookup[item.id]);
    }
  });

  return rootItems;
}

const flatData = [
  {"id": 1, "name": "Alice", "parentId": null},
  {"id": 2, "name": "Bob", "parentId": 1},
  {"id": 3, "name": "Charlie", "parentId": 1},
  {"id": 4, "name": "David", "parentId": 2}
];

console.log(JSON.stringify(buildTree(flatData), null, 2));

function checkCircularReference(items) {
  const visited = new Set();
  for (const item of items) {
    let current = item;
    while (current) {
      if (visited.has(current.id)) {
        throw new Error('Circular reference detected');
      }
      visited.add(current.id);
      current = lookup[current.parentId] || null;
    }
  }
}