給我一個typescript 數組轉樹的方法

以下是一个 TypeScript 的数组转树的方法：

interface TreeNode {
  id: number;
  parentId: number;
  children?: TreeNode[];
}

function arrayToTree(arr: TreeNode[]): TreeNode[] {
  const map: { [key: number]: TreeNode } = {};
  const roots: TreeNode[] = [];

  arr.forEach((node) => {
    map[node.id] = { ...node, children: [] };
  });

  arr.forEach((node) => {
    const parent = map[node.parentId];
    if (parent) {
      parent.children?.push(map[node.id]);
    } else {
      roots.push(map[node.id]);
    }
  });

  return roots;
}

使用示例：

const arr = [
  { id: 1, parentId: 0 },
  { id: 2, parentId: 1 },
  { id: 3, parentId: 1 },
  { id: 4, parentId: 2 },
  { id: 5, parentId: 2 },
  { id: 6, parentId: 3 },
];

const tree = arrayToTree(arr);
console.log(tree);

输出结果：

[
  {
    "id": 1,
    "parentId": 0,
    "children": [
      {
        "id": 2,
        "parentId": 1,
        "children": [
          {
            "id": 4,
            "parentId": 2,
            "children": []
          },
          {
            "id": 5,
            "parentId": 2,
            "children": []
          }
        ]
      },
      {
        "id": 3,
        "parentId": 1,
        "children": [
          {
            "id": 6,
            "parentId": 3,
            "children": []
          }
        ]
      }
    ]
  }
]
``