no issue
- move members loading code into `members` controller so that it's more accessible to other areas of the app
- add `refreshData()` to the `members` controller which forces members list and stats to be re-fetched
- call `members.refreshData()` after successful upload of members import file
- store range/days in `membersStats` service so that it's remembered across refreshes and component renders
no issue
- the "days changed" logic was incorrect so we were always performing new fetches rather than using existing data
- added a minor improvement that returns an in-progress fetch promise if we have one and params haven't changed - avoids triggering unnecessary extra fetches in the rare occasions the chart is re-rendered before a previous stats fetch has finished
no issue
- "stale data" logic was incorrect so we were always returning `undefined` from `membersStats.fetch()`
- improved behaviour of the chart when stats are not available or are loading
no issue
- added a `member-stats` service to keep member stats state outside of the chart component's lifecycle
- returns memoized member stats when fetching if the query hasn't changed and the data is less than a minute old
- reduces potentially heavy network requests when quickly navigating between members list and other screens
