Biggus also has such a function: https://github.com/SciTools/biggus/blob/master/biggus/__init__.py#L2878

It handles newaxis outside of that function in: https://github.com/SciTools/biggus/blob/master/biggus/__init__.py#L537.

Again, it only aims to deal with orthogonal array indexing, not numpy fancy indexing.

I'd be surprised if Dask.array didn't have a similar function too.