test of concept for a javascript async-paginated buffer with both forward and reverse iterator

requirements (we use this as source for writting the test)

There is a large source array of fixed size (i.e, 1010 records) that must be retrieved through some paginated service.

The page size has a max, (i.e. 100 records) but may return less events (if it is near to either the end or the start of the source array).

The local buffer is initialized with a fixed size, equals to the size of the max_page

The local buffer may be iterated either in forward or backward mode

A threshold may be provided to trigger the pagination service once the iterator pass some point.

So, for the end user it must be completely opaque the retrieval of pages. it must be able to iterate the whole records in any direction.