reactive-programming

问题 I'm trying to run this example. I have these errors when I start running it: npm ERR! missing script: start npm ERR! A complete log of this run can be found in: npm ERR!/home/username/.npm/_logs/2018-04-15T09_19_49_453Z-debug.log any help? 回答1: your scripts of package.json should be: "scripts": { "start": "node ./examples/app.js", "test": "echo \"Error: no test specified\" && exit 1" } 回答2: It looks like there is no start command in scripts i.e in your package.json file. Below is the start

问题 I have a seed value Triangle (Bool) and an observable that emits values Circle (Int) . My intention is to generate a new observable (Triangle, Circle) each time a value is emitted from that observable, transforming the Triangle value negating the current value. This is my marble diagram: But I cannot achieve it, and I don't know if scan is the correct operator. This is my code: typealias Triangle = Bool typealias Circle = Int func scan() { let triangle: Triangle = false circleObservable .scan

问题 I am wondering if it is possible to use Observables in components, and which other components can subscribe to? BugListComponent - component is injected in the boot.ts file where I load all my services (where boostrap is located) import {Subject, BehaviorSubject} from 'rxjs/Rx'; viewBugList$: Subject<boolean>; constructor() { this.viewBugList$ = new BehaviorSubject<boolean>(false); } // Called from template, sends in 'true' private enableIEview(enable: boolean) { if(enable) { this.viewBugList

问题 For instance, var interval = Rx.Observable.interval(1000); interval.subscribe(x => console.log(x)); And var deferred = Rx.Observable.defer(()=> return interval); deferred.subscribe(x=> console.log(x)); seem to do the same thing. It seems to that observables are by default "deferred". What is defer useful for? 回答1: defer takes a parameter function which returns an observable. The operator itself returns an observable, as most operators do. When that defer observable is subscribed to, it

问题 I send request - get an array of data. In order to manipulate that data I need to flatten it, so I can use it as a stream of entities not stream of array of entities but, then on side-effect I want those entities appear in the UI at once, not one by one, so it updates UI only ones at a time. Let's say I have a code like this: // this generates a sequence of objects - getCasesStream sends an ajax request, // whenever dateRange changes casesStm = dateRangeStm.flatMapLatest(getCasesStream)

问题 How can i retry if mapping/processing of an element in the stream fails? I have tried setting the decider in materializer but it does not offer retry. It simply maps exception to Supervision stage. Thanks 回答1: Consider it as a tip rather than complete answer. I recently implement similar functionality with futures and mapAsync . There is a library called retry for retrying futures with different strategies such as pause or back off. But this method have a problem that because akka streams use

问题 Reproducable example: server.R library(shiny) shinyServer( function(input, output, session) { myDf <- reactiveValues(myData = NULL) problematicDf <- reactiveValues(test = NULL) observeEvent(input$myButton, { myDf$myData <- df }) observe({ output$myTestUi <- renderUI({ selectInput(inputId = 'mySelection', label = 'Selection', choices = levels(myDf$myData$z), multiple = T, selected = c(levels(myDf$myData$z)[1]) ) }) }) observe({ problematicDf$test <- subset(myDf$myData, ((myDf$myData$z %in%

问题 I'm learning reactive extensions (rx) in .NET and I'm struggling a little bit with what a "subscription" really is and when it is used. Lets take some sample data, taken from this thread: using System; using System.Reactive.Linq; using System.Threading; namespace ConsoleApp1 { class Program { class Result { public bool Flag { get; set; } public string Text { get; set; } } static void Main(string[] args) { var source = Observable.Create<Result>(f => { Console.WriteLine("Start creating data!");

问题 As an exercise I'm trying to build 2 dependent streams which update one another. The test application is simply an "Inches <-> Centimeters" converter, with both inputs editable. The issue I am experiencing is that I cannot get how can I stop recursion that causes one field change. To better explain the issue let's have a look at the relevant part of code: var cmValue = new Rx.BehaviorSubject(0), inValue = new Rx.BehaviorSubject(0); # handler #1 cmValue.distinctUntilChanged().subscribe

问题 I have an issue with a reactive chain relying on flatMap() and switchIfEmpty() . For some reason, one of the Mono does not emit anything... This is the public handler method calling the others: //Throws: NoSuchElementException: Source was empty public Mono<ServerResponse> createUser(ServerRequest serverRequest) { Hooks.onOperatorDebug(); Mono<User> userMono = serverRequest.bodyToMono(User.class); return validateUser(userMono) .switchIfEmpty(saveUser(userMono)) .single(); } This is the first