[feature] Expose newly created items list in confirmChange

[JeffWatson0]

Description
Issue: Using the provided props users are able to prevent dragging of items, however we cannot prevent the re-ordering of items.

Feature Request - expose the new list of items in the confirmChange function. Allow consumers to use this data when evaluating a change.

Additional context
Will provide a PR for this change 😄

[primetwig]

hi. you can simply check if new parent is the same as current parent, then it is reordering, so you can prevent that. does that make sense?

[JeffWatson0]

Hi @primetwig, thanks for getting back to me so quickly!
Thanks for the suggestion - your solution works great for nested children.

However, I am not able to find a way to make it work when reordering top-level items.

For my use case, I want to "hardcode" item A at index 0, but allow items B and C to move. I use the disableDrag function for item A (which works perfectly!)
Ex: Start

A
B
C

The problem happens when I try to move B to index 0.
Ex: After Moving B

B
A
C

props to confirmChange: dragItem = Item B, destinationParent = null

For these top-level item changes, the destinationParent is always null. There is nothing sent to confirmChange that can tell me a little more context about the other items that have changed, so we can asses the validity of the move.

[primetwig]

I see. It looks like destination index or the whole path (like in onChange) would help. Let me check what I can do...

[JeffWatson0]

May I suggest you simply move the confirmChange call to after creation of the "new" items, and include the complete new items in the confirmChange signature?

Edit: like onChange would be perfect! 👍

[primetwig]

the thing is that moving item into position may have several options as to final result and I need to consider all of them.
example:

• A
• B
  • C

when you move A over B, it checks if it is allowed to put A into B, but in case it is not – it should also check if it is allowed to swap A with B, thought it does not check that.
so I need to handle that in the first place which will also give me (and you) more info in confirmChange in the end.

[JeffWatson0]

PR open here: #113

Thanks for this library!