#System Design Cheatsheet
Picking the right architecture = Picking the right battles + Managing trade-offs
##Basic Steps
In this gist I would like to describe an idea for GraphQL subscriptions. It was inspired by conversations about subscriptions in the GraphQL slack channel and different GH issues, like #89 and #411.
At the moment GraphQL allows 2 types of queries:
querymutationReference implementation also adds the third type: subscription. It does not have any semantics yet, so here I would like to propose one possible semantics interpretation and the reasoning behind it.
| public class Pager<I, O> { | |
| private static final Observable FINISH_SEQUENCE = Observable.never(); | |
| private PublishSubject<Observable<I>> pages; | |
| private Observable<I> nextPage = finish(); | |
| private Subscription subscription = Subscriptions.empty(); | |
| private final PagingFunction<I> pagingFunction; | |
| private final Func1<I, O> pageTransformer; |
(by @andrestaltz)
So you're curious in learning this new thing called (Functional) Reactive Programming (FRP).
Learning it is hard, even harder by the lack of good material. When I started, I tried looking for tutorials. I found only a handful of practical guides, but they just scratched the surface and never tackled the challenge of building the whole architecture around it. Library documentations often don't help when you're trying to understand some function. I mean, honestly, look at this:
Rx.Observable.prototype.flatMapLatest(selector, [thisArg])
Projects each element of an observable sequence into a new sequence of observable sequences by incorporating the element's index and then transforms an observable sequence of observable sequences into an observable sequence producing values only from the most recent observable sequence.