联想查询，数组中id和label，相互查询

const treeData = [
  {
    id: 1,
    label: 'a',
    children: [
      {
        id: 11,
        label: 'aa',
        children: [
          {
            id: 111,
            label: 'aaa',
            children: [
              {
                id: 1111,
                label: 'aaaa',
                children: [],
              }
            ]
          }
        ]
      },
      {
        id: 12,
        label: 'ab',
        children: [
          {
            id: 121,
            label: 'aba',
            children: [
              {
                id: 1211,
                label: 'abaa',
                children: [],
              }
            ]
          }
        ]
      },
    ]
  },
  {
    id: 2,
    label: 'b',
    children: [
      {
        id: 21,
        label: 'ba',
        children: [
          {
            id: 211,
            label: 'baa',
            children: [
              {
                id: 2111,
                label: 'baaa',
                children: [],
              }
            ]
          }
        ]
      }
    ]
  }
];

代码逻辑：

function findLabelsByIds(tree, ids) {
  const labels = [];
  
  function findNode(nodes, targetId) {
    for (const node of nodes) {
      if (node.id === targetId) {
        return node;
      }
      if (node.children && node.children.length) {
        const found = findNode(node.children, targetId);
        if (found) return found;
      }
    }
    return null;
  }

  for (const id of ids) {
    const node = findNode(tree, id);
    if (node) {
      labels.push(node.label);
    } else {
      labels.push(null); // 如果没找到，可以返回 null 或自定义默认值
    }
  }

  return labels;
}