const [treeData, setTreeData] = useState([
      {
        title: 'parent 1',
        key: '0-0',
        icon: <UserAddOutlined />,
        children: [
          {
            title: 'parent 1-0',
            key: '0-0-0',
            icon: <UserAddOutlined />,
            children: [
              {
                title: 'leaf',
                key: '0-0-0-0',
                icon: <UserAddOutlined />,
              },
              {
                title: 'leaf',
                key: '0-0-0-1',
                icon: <UserAddOutlined />,
              },
            ],
          },
          {
            title: 'parent 1-1',
            key: '0-0-1',
            icon: <UserAddOutlined />,
            children: [
              {
                title: 'sss',
                key: '0-0-1-0',
                icon: <UserAddOutlined />,
              },
            ],
          },
        ],
      },
    ]);


const insertDataHandler = (formData) =>{

  // i need to add this element on specific parent's children list
  const parentId = formData.pId;
  let element = {
    title: formData.nNode,
    key: formData.Id,
    icon: <UserAddOutlined />,
  }
}

in insertDataHandler the element was created, and also I have a parent id so what I need to do is the parent id will check all the keys of treeData and add to this specific parent's children's array where key is match, if the children are not exist then create the array then insert into that array