rxjs

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 am building an Angular 2 web app using Typescript and am trying to switch from Angular2-beta-17 to Angular2-RC1. I am struggling to get the imports of the RXJS operators to work. I am using SystemJS as a module loader, and suspect this is were the problem lies. I copy the file bundles I need from my node modules to a lib-folder and then include the files in the index.html file like this (the commented sections are some of the many combinations of different attempts for solutions I have

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 I have next function: saveTable() { ... let promises = []; for (index = 0; index < this._TOTAL.length; ++index) { let promise = this.db.object(ref).update(this._TOTAL[index]); promises.push(promise); } Observable.forkJoin(promises).subscribe(() => { this.messagesService.createMessage('success', `Saved`); this.router.navigate(['/dashboard/my-calculations']); }) } How can i handle error in this case? Actually, i just need to use then and catch after all my promises resolve, so using forkJoin

问题 As part of migrating my project from angular 5 to 6 I had to update the way RXJS6 does things. So this this.filteredList = this.autoComplete.valueChanges .startWith(null) .map(val => val ? this.filter(val) : this.list.slice()); changed to this this.filteredList = this.autoComplete.valueChanges.pipe( startWith(null), map(val => val ? this.filter(val) : this.list.slice())); It seems the compiler can't infer type anymore as I get Severity Code Description Project File Line Suppression State

问题 I'm struggling with something which I can't understand why it is happening . Looking at this example : const source = Rx.Observable.of(1).share(); source.subscribe(console.log); //1 source.subscribe(console.log); //1 This prints "1" twice. AFAIK share looks at refCount . But if we look at it - refcount should be ZERO here : const source = Rx.Observable.of(1).share(); source.subscribe(console.log); ^-- 1)refCount=1 2)value emitted - closing subscription ( complete) 3)refCount=0 source

问题 I am trying to create an observable response where I make one http call and then before returning the response, I make another http call to populate the return object of the first call as shown below. getOrderWithItems(orderId: string, includes: Set<OrderInclude>): Observable<OrderDto> { return this.getOrder(orderId, includes) .map(order => { this.searchItems().subscribe( items => { order.items = items.results; return order; } ) }); } The compiler gives an error: Type 'Observable' is not

问题 In my angular application, I want user to be able to upload few images and then I want to display their preview using subjects and observables. My component.ts file has these properties: uploadPicturesSubject$: Subject<any[]> = new Subject<any[]>(); previewUrls$: Observable<any[]> = this.uploadPicturesSubject$.asObservable(); previewUrls: any[] = []; Then in my event handler for the (change) event (when user uploads photos) I have the following code: ... const reader: FileReader = new

问题 I'm trying to figure out why my use of retry is not working in this example: http://jsbin.com/bobecoluxu/edit?js,output var response$ = Rx.Observable.fromPromise( $.ajax({ url: 'http://en.wikipedia.org/w/api.php', dataType: 'jsonp', data: { action: 'opensearch', format: 'json', search: term } })) .retry(3); I've wrapped the ajax call in an Observable in the searchWikipedia function, but if I try to force the failure of this call by turning off the wifi or throwing an exception by the related

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!");