how to flattern a tree data with views

[dodoto]

Question

• [x] I've checked documentation and searched for existing issues
• [ ] I tried GitHub Discussions

I have a tree object like this:

[ 
  {
    id: 1, 
    isOpen: true,
    children: [{id: 1-1, isOpen: false, children: []}]
  }
]

after flattern get this:

[{id: 1, isOpen: true, children: []}, {id: 1-1, isOpen: false, children: []}]

what should I do can get this with views.