Propagate additional information to nodes with INode metadata

[megbailey]

• Adding optional metadata: any prop to INode
  • Adding optional metadata: any prop to ITreeNode
  • Do a shallow copy of meta data when flattening ITreeNode. Ideally, it would be great if this was a deep copy but I need some help for that
  • Adding 2 tests to validate that metadata exists after flattening tree and metadata can be accessed in nodeRenderer

Attempting to resolve https://github.com/dgreene1/react-accessible-treeview/issues/86 and the comments brought up in https://github.com/dgreene1/react-accessible-treeview/pull/101

[dgreene1]

@mellis481 this PR has the fixes i requested. It was very nice of @megbailey to make the changes that the previous submitter was asked to make. Can you and @yhy-1 get this approved and merged?

Sincerely, from the beach, Dan

[dgreene1]

@kpustakhod I fixed the no-any lint issues. @megbailey that makes this solution fully generic and it now even infers the type of the metadata.

Can you all take a look and see if it looks good to you?

[dgreene1]

@kpustakhod please merge this

[sandro768]

Please merge it 🥶

[dgreene1]

Thank you @megbailey for you contributions. Thank you @sandro768 for the push. We love our community. :)

[Pearce-Ropion]

What is the purpose of doing a shallow clone on the metadata object? Presumably, metadata is just used for additional data that can be used to render large trees and will likely only contain static properties. If anything, I would assume (as a user) that any metadata object that is passed to a given node could be mutated as that is how javascript objects typically work. By shallow cloning the metadata object, we are effectively breaking the expected behavior of the data being passed to the tree.

Furthermore, I don't think nodes should only accept a non-nested metadata object purely so that the flattenTree function can do a shallow clone. For cases where the user is manually building the INode array, users shouldn't be limited to a single level of metadata since we aren't doing any additional metadata manipulation for them.

And finally, boolean should be added to the IFlatMetadata type.

edit: I wrote up a longer post in #129