Brandur e3cc91ded2 Support backwards pagination with list's #auto_paging_each (#865)
* Support backwards pagination with list's `#auto_paging_each`

Previously, `#auto_paging_each` would always try to paginate forward,
even if it was clear based on the list's current filters that the user
had been intending to iterate backwards by specifying an `ending_before`
filter exclusively.

Here we implement backwards iteration by detecting this condition,
reversing the current list data, and making new requests for the
previous page (instead of the next one) as needed, which allows the user
to handle elements in reverse logical order.

Reversing the current page's list is intended as a minor user feature,
but may possibly be contentious. For background, when backwards
iterating in the API, results are still returned in "normal" order. So
if I specifying `ending_before=7`, the next page would look like `[4, 5,
6`] instead of `[6, 5, 4]`. In `#auto_paging_each` I reverse it to `[6,
5, 4]` so it feels to the user like they're handling elements in the
order they're iterating, which I think is okay. The reason it might be
contentious though is that it could be a tad confusing to someone who
already understands the normal `ending_before` ordering in the API.

Fixes #864.

* Allow `ending_before` and `starting_after` to remain in hydrated list object
2019-10-10 10:11:12 -07:00
..
2019-08-20 11:35:24 -07:00