Removing the last item in a Trackable collection breaks paginated grid

[maier49]

After removing the last item in a paginated grid's trackable collection the navigation displays negative numbers. Additionally, once the grid is in this state new rows added to the trackable collection are not rendered by the grid. This JSFiddle demonstrates this bug: http://jsfiddle.net/jL3qrm0a/1/ on master, but it exists in at least 0.4.0 as well.

[maier49]

I believe the issue is caused by _onNotification passing 0 as a page number to gotoPage. Changing these lines: https://github.com/SitePen/dgrid/blob/bbc904cc4ae6516617591c7aa630e7cc32fcdc00/extensions/Pagination.js#L463-L466 by adding || 1 in the call to gotoPage , or wrapping the argument in a Math.max(0, ... if we are concerned about potentially passing a negative page number resolves the issue.