[Vue warn]: Unknown custom element: <TreeNode> - did you register the component correctly? For recursive components, make sure to provide the "name" option.
递归式引用组件，比如A组件引用B组件，B组件引用C组件，C组件又引用A组件之类的
解决方案是，将import引入改为components内引入：
components: {
TreeNode: () => import('./TreeNode.vue')
}
