Is it possible to sort the collection?

[BryanJBryce]

I try to sort and it gets turned back into a normal array.

[mbrandonw]

You can use the in-place mutation version, sort(by:). By default, Sequence defines sorted as returning an array, so that kind of forces our hand here. We could technically overload sorted on IdentifiedArray to return another IdentifiedArray, but it wouldn't work generically.

For example, even if we defined a new sorted to return IdentifiedArray, it will be the case that if you erase the type to any Sequence and then call sorted you will always get an Array:

var xs = IdentifiedArray<String, String>(id: \.self)
type(of: xs.sorted())  // IdentifiedArray<String, String>

var ys = xs as any Sequence<String>
type(of: ys.sorted())  // Array<String>

That behavior can be surprising, which I think is why we chose not to define sorted.

[mbrandonw]

Hey @BryanJBryce, after chatting with Stephen we think this could be a good thing to add to the library. Do you want to take a crack at it by opening a PR?