从数组生成树，并将父字段的表示形式更改为object而不是ID

class TreeNode {
  constructor(id, value, parent) {
    this.id = id;
    this.value = value;
    this.parent = parent;
    this.children = [];
  }
}

function generateTree(nodes, parentField) {
  // 创建一个空的节点映射表，用于根据id查找节点
  const nodeMap = {};

  // 构建节点映射表
  for (const node of nodes) {
    nodeMap[node.id] = new TreeNode(node.id, node.value, null);
  }

  // 构建树结构
  for (const node of nodes) {
    const parentNode = nodeMap[node[parentField]];
    const currentNode = nodeMap[node.id];

    // 将当前节点添加到父节点的子节点列表中
    if (parentNode) {
      parentNode.children.push(currentNode);
      currentNode.parent = parentNode;
    }
  }

  // 返回根节点
  return Object.values(nodeMap).find(node => !node.parent);
}

const nodes = [
  { id: 1, value: 'A', parent: null },
  { id: 2, value: 'B', parent: 1 },
  { id: 3, value: 'C', parent: 1 },
  { id: 4, value: 'D', parent: 2 },
  { id: 5, value: 'E', parent: 2 },
  { id: 6, value: 'F', parent: 3 },
];

const tree = generateTree(nodes, 'parent');
console.log(tree);

TreeNode {
  id: 1,
  value: 'A',
  parent: null,
  children: [
    TreeNode { id: 2, value: 'B', parent: [Circular], children: [Array] },
    TreeNode { id: 3, value: 'C', parent: [Circular], children: [Array] }
  ]
}

class TreeNode {
  constructor(id, value, parent) {
    this.id = id;
    this.value = value;
    this.parent = parent instanceof TreeNode ? parent : null;
    this.children = [];
  }
}

function generateTree(nodes, parentField) {
  // 创建一个空的节点映射表，用于根据id查找节点
  const nodeMap = {};

  // 构建节点映射表
  for (const node of nodes) {
    nodeMap[node.id] = new TreeNode(node.id, node.value);
  }

  // 构建树结构
  for (const node of nodes) {
    const parentNode = node[parentField];
    const currentNode = nodeMap[node.id];

    // 将当前节点添加到父节点的子节点列表中
    if (parentNode) {
      const parent = nodeMap[parentNode.id];
      if (parent) {
        parent.children.push(currentNode);
        currentNode.parent = parent;
      }
    }
  }

  // 返回根节点
  return Object.values(nodeMap).find(node => !node.parent);
}

const nodes = [
  { id: 1, value: 'A', parent: null },
  { id: 2, value: 'B', parent: { id: 1 } },
  { id: 3, value: 'C', parent: { id: 1 } },
  { id: 4, value: 'D', parent: { id: 2 } },
  { id: 5, value: 'E', parent: { id: 2 } },
  { id: 6, value: 'F', parent: { id: 3 } },
];

const tree = generateTree(nodes, 'parent');
console.log(tree);

TreeNode {
  id: 1,
  value: 'A',
  parent: null,
  children: [
    TreeNode { id: 2, value: 'B', parent: [Circular], children: [Array] },
    TreeNode { id: 3, value: 'C', parent: [Circular], children: [Array] }
  ]
}