Combine sounds like a great framework, and is finally an excuse to dig into reactive programming. I am finding the documentation a bit spare though around the concept of promise chaining.
I am hoping to find a good example of promise chaining for combining two serial asynchronous functions -- that is, use the result of one to populate the second. Here's something I was working with as a potential use case:
- given a UIViewController with a MKMapView
- user pans the map, and I can store the region when mapView:regionDidChangeAnimated is called in a @published var (e.g.
)theRegion - create a pipeline that takes
and then does the following:theRegion
-- does an asynchronous function to find all PoIs in the region
-- does another asynchronous function to find distance for each PoI to the center of the map
-- finally updates UI by highlighting closest PoI
I am beginning to grok Futures in general, but have not done enough to fully understand it. For a similar idea I have used a lot of OperationQueues and state management and it's a mess... hope this can help simplify that in the end.
A bonus would be showing how to execute the async functions off the main thread.
