Support short polling

Sometimes it might be handy to refresh query data, which could allow to have more “real-time” user experience. This is how I would go about it:

1. To RequestAction add meta.pool: number (in seconds), this would be an interval, how often queries should be refetched automatically
2. We could implement it as a separate middleware (probably it would go even as 1st one in the stack)
3. Of course this middleware should be disabled when running with ssr: 'server'
4. PollingMiddleware would just pass all actions through, but also it would check for queries with meta.poll, for which it would activate setInterval, repeating those actions, dispatching them again after x seconds
5. I think that dispatched query from this new middleware could also add meta.pollCounter: number, it could show us which time a given query is repeated, and also this could prevent poll looping - we shouldn’t create interval again for a query which is result of this middleware, otherwise we would have multiple intervals for the same query
6. Making a new request of the same type (type + requestKey) without meta.pollCounter should clear current interval (it really means than a new query was dispatched, not from middleware but outside), and, depending on meta.poll, possibly set new interval
7. we should add stopPolling action which should have the same arguments like for example abortRequests
8. probably new flag should be added to resetActions but for now I won’t provide details as resetActions is work in progress on pure-react branch

[klis87]

@iwan-uschka @favger released in https://github.com/klis87/redux-requests/releases/tag/%40redux-requests%2Fcore%401.5.0

note that I didn’t implement pause and resume polling actions, because it can be just achieved by dispatching stopPolling and then, in a proper time by dispatching a given query with meta.poll again

[klis87]

Just in case, if anyone started working on this, please let me know, as probably this is the next on my list, as I just published new version focused on React. If not, that’s totally fine, I just don’t want to duplicate our efforts 😃