rxjs

问题 I'm trying to create a RX stream that will execute a list of XHR calls async and then wait for them to complete before going to the next call. To help explain this could be written like this in normal JS: try { await* [ ...requests.map(r => angularHttpService.get(`/foo/bar/${r}`)) ]; } catch(e) { throw e } // do something This is the code I was trying but its running them individually and not waiting for them all to complete before proceeding. (This is a NGRX Effect stream so it is slightly

问题 I have an observable producing Users that have an isLoading property, such that this yields the expected result: {{ (user$ | async).isLoading }} I would like to be able to use this isLoading property in an HTML attribute, like this: <button md-raised-button type="submit" [disabled]="user$.isLoading">Login</button> but no syntax I use seems to do the trick. How do you subscribe to an observable like this in an HTML attribute? 回答1: You can use async pipe in html tag like in example below, just

问题 How can we transform a Subject into an Observable in RxJs 5 ? This functionality is useful for example when we want to expose the Subject for subscription but don't want to yield control of calling next() on it, and prefer to keep the issuing of new values private. The docs (see here) mention something like this: var subject = new Rx.Subject(); var obs = subject.asObservable(); But in RxJs 5 this currently does not work (alpha 8), we get the following error: "TypeError: subject.asObservable

问题 Context: I am working on implementing @ngrx/effects within an @ngrx/store project and studying the example app. Question: In the BookEffects class file, line #50, why is takeUntil(...) used instead of take(1) ? Both would seem to accomplish the same thing in this case. @Injectable() export class BookEffects { constructor(private actions$: Actions, private googleBooks: GoogleBooksService) { } @Effect() search$: Observable<Action> = this.actions$ .ofType(book.ActionTypes.SEARCH) .debounceTime

问题 I have http interceptor. In that interceptor, before I change the request, I need a loader to turn on. What really worries me is that I end up having lots of switchmaps. why? loader is asynchronous I also need to translate the message passing from interceptor to loader service. translating message is also asyncrhonous. and in interceptor, i should run the request when loader and translating finishes What I do in my loader service showLoader(message){ return this.translateService.get(message)

问题 I'm trying to create custom pipe on asynchronous pipe, I tried many solutions, but still not working. Here is the snippet of code. product.sort.ts - custom pipe import { PipeTransform, Pipe } from '@angular/core'; import { Observable } from 'rxjs/Observable'; @Pipe({ name: 'sortByName' }) export class ProductPipe implements PipeTransform{ /*transform(values: Array<any>, term:string){ return values.filter(obj => obj.pname.startsWith(term)) }*/ //CODE NOT WORKING >>>>> transform($value:

问题 Assuming i have the following rxjs pipe: start$.pip( map((id)=> {}), //I want to save the "id" value to be used in the end of the pipe map(...), switchMap(...), map(...), switchMap(...), map(...), switchMap(...), switchMap(...)//I need the original "id" value here ).subscribe() Is there a way to keep the 'id" value throughout the pip so it can be used at the end of the pipe? Motivation: It comes often in NGRX effects where i want to use the original payload data of the triggering source

问题 I have an array of objects from which I need to pass each object separately into async method (process behind is handled with Promise and then converted back to Observable via Observable.fromPromise(...) - this way is needed because the same method is used in case just single object is passed anytime; the process is saving objects into database). For example, this is an array of objects: [ { "name": "John", ... }, { "name": "Anna", ... }, { "name": "Joe",, ... }, { "name": "Alexandra", ... },

问题 I am new to Angular2 and Observable, I want to check if a Observable getRoles which is of type Observable<string[]> contains a string. public hasRole(name: string): boolean { // getRoles is of type Observable<string[]> let getRoles = this.tokenService.getTokenInformation().map(element => element.roles); if (/* check if name is inside of getRoles */) { return true; } return false; } 回答1: Observables are asynchronous so you can't use let getRoles = ...map(...) . The map() method is not executed

问题 I cant seem to get my delete request to work. I have finished all of the get requests but now I'm stuck on delete and can't seem to wrap my head around it. The console.log'd URL is always correct and the delete request works fine via Postman. Got any ideas? HTML <button class="button button3" (click)="delTicket()"><span class="fa fa-trash"></span></button> TS delTicket(){ this.id = this.route.snapshot.params.id; this.ticketService.deleteTicket(this.id); } Service deleteTicket(id): Observable