reactive-programming

I've seen patters like this: Observable<String> nameChanges = nameDataSource.changes().share(); // One subscriber autoUnsubscribe(nameChanges.subscribe(() -> { ... })); // Another subscriber autoUnsubscribe(nameChanges.map(...).filter(...).subscribe(...)); // autoUnsubscribe is called when the UI is torn down My question is: Why is it necessary to call share() whenever I want to listen to the Observable in multiple places? Why is not share() the default behavior for all observables? It would be nice if the code above worked the same even without .share() . I would not have to think about when

I try to query all people data from the swap api . The URL swapi.co/api/people returns an object with an people array and the URL(swapi.co/api/people/?page=2) where I get the next data from. What I want to do is that the subscribe method updates the angular component every time a new page is available. I’m new to the reactive programming model. How can I implement a while loop or a sequence of Observables? This works for the first page: getAllPeople(): Observable<Person[]> { let nextUrl = http://swapi.co/api; let source = Observable.create(observer => { this.http.get(nextUrl, { headers: this

Observable.fromCallable() is great for converting a single function into an Observable. But how do you handle checked exceptions that might be thrown by the function? Most of the examples I've seen use lambdas and "just work". But how would you do this without lambdas? For example, see the quote below from this great article : Observable.fromCallable(() -> downloadFileFromNetwork()); It's a one-liner now! It deals with checked exceptions, no more weird Observable.just() and Observable.error() for such easy thing as deferring code execution! When I attempt to implement the above Observable

I'm familiar with the basics of shiny but struggling with something here. I would like to be able to add a ggplot layer when a point is clicked to highlight that point. I know this is possible with ggvis and there is a nice example in the gallery, but I would like to be able to use nearPoints() to capture the click as ui input. I have tried something (see below) which works apart from the ggplot layer appears and then disappears. I have tried all kinds of edits to this with reactive() , eventReactive() and so on. Any help is much appreciated... library(shiny) library(ggplot2) shinyApp( ui =

Is it equivalent/better to work with the Event module on Event type or with Observable on the publish property of an event Functionally it seems equivalent, and I guess the difference is 'semantic' : Are we inside the boundary where it makes sense to have access to the internal state of the event ? Or are we considering this event interface as a passive source from which a stream was exposed to us Is that the correct thinking ? The main difference between Event and Observable is in how they handle state and un-subscription. Event functions attach to the source event and do not give you any way