`getChildren` isn't implemented for `TreeCollection`

[BenGladman]

Provide a general summary of the issue here

I'm trying to implement a menu using the useMenu hook. This requires me to use a tree state.

To get the child nodes of a section, if I try to use item.childNodes I get a deprecation warning. But the suggested alternative collection.getChildren(key) isn't implemented for TreeCollection. So as far as I can see there isn't currently any way of implementing this without triggering a warning.

🤔 Expected Behavior?

component below should show the O1 item:

function MyComponent() {
  const treeState = useTreeState({ 
    children: [<Section key="S1"><Item key="O1" /></Section>]
  });

  return (<pre>
    {[...treeState.collection.getChildren('S1')]}
  </pre>);
)

😯 Current Behavior

Component above crashes because getChildren is not implemented

💁 Possible Solution

implement getChildren on TreeCollection, or un-deprecate childNodes property on Node interface

🔦 Context

I'm trying to implement a menu using the useMenu hook.

🖥️ Steps to Reproduce

function MyComponent() {
  const treeState = useTreeState({ 
    children: [<Section key="S1"><Item key="O1" /></Section>]
  });

  return (<pre>
    {[...treeState.collection.getChildren('S1')]}
  </pre>);
)

Version

react-stately 3.36.1

What browsers are you seeing the problem on?

Chrome

If other, please specify.

No response

What operating system are you using?

Windows

🧢 Your Company/Team

No response

🕷 Tracking Issue

No response

[LFDanLu]

Could you do something like this:

react-spectrum/packages/@react-spectrum/menu/src/MenuSection.tsx

Line 82 in 77b3442

{[...getChildNodes(item, state.collection)].map(node => {

instead? Alternatively, if you are looking to implement something using RAC collections API you could emulate the RAC Menu implementation. We will be updating the hook docs in the future to use the RAC collections API to make this easier as well.

That being said, is there a particular reason you dropped to the hooks level here instead of using RAC Menu?