rxjs

问题 I was reading up on how to share data between unrelated components in Angular from the "Unrelated Components: Sharing Data with a Service" section of the tutorial here. I see how this example works for the string they are trying to share across their components, but my data type is a little more complex: Namely, I think my BehaviorSubject should look like this: private currentPopulationSource: BehaviorSubject<Population> = new BehaviorSubject<Population>(new Population(new Array<Organism>()))

问题 The following Rx.Observable.zip( Rx.Observable.of(1,2), Rx.Observable.of("a")) .subscribe(p => console.log(p)) produces 1,a which makes sense, but what I want it to produce is 1,a 2,undefined I want to pad the shorter observable with undefineds until the longer one completes. Any suggestions? 回答1: I realise adding delay can turn the .of operator async and with scan you can replace the same value with undefine Rx.Observable.combineLatest( Rx.Observable.of(1,2).delay(0), Rx.Observable.of("a"))

问题 I am new to Angular and RxJS operators. I need help in one of the scenario in which I upload multiple documents at once in the backend (Rest API). Processing the documents takes time in backend my my observable gets timeout in 2 minutes. Now I am thinking of the solution in which I will send the post request to backend and will not wait for the response. And subscribe whenever response is ready by backend. Please suggest if my approach is ok ? and how to achieve it in angular 8 with and Rxjs

问题 So I am trying to build a list component reactively by angular and RxJS. the list has a lot of features like: search by word change page number change page size filter by field(s) sort search service code: private seachItemSubject = new BehaviorSubject<string>(""); private pageLimitSubject = new BehaviorSubject<number>(10); private pageNumberSubject = new BehaviorSubject<number>(0); private orderingSubject = new BehaviorSubject<ListOrder>({}); private filteringSubject = new BehaviorSubject

问题 Why Event Emitter can't use in service in angular 6? In Angular documentation they mentioned, "Use in directives and components to emit custom events" 回答1: Because in services all waht you have to do is manipulating data, if you want to notify the data changes you can use Subjet or BehaviorSubjet . EventEmitter is generally used to notify changes from child to parent and as said is supposed to be used only for @Output . please take a look at this link 来源： https://stackoverflow.com/questions

问题 Update - error solved I solved this error by issuing command: webpack --config webpack.config.vendor.js If however anyone wishes to explain to me why was webpack --config necessary I would gladly upvote and accept your answer. When must I reconfigure webpack - any time I update any of the npm packages or dependencies? Original question I'm following the Tour of Heroes and got stuck at the final chapter "Http", at this step. When I go and try to fetch my hero list I get an error in Chrome

问题 I am creating a web app unsing Angular 4 and RxJs. In one part of my code I am creating a websocket using: Observable.websocket(url); function. Here is my code: /** * Tries to open a websocket connection to a given URL. * @param url * @param subscription Previous subscription to this socket (it may be necessary to close it before proceeding) * @returns an object containing the subscription and the websocket subject. */ private openConnection(url: string, subscription: Subscription): { socket$

问题 I was thinking of using Observables to add .flatMapLatest() & .throttle() functionality to a Promise based HTTP client library (axios). But I'm not going to change the whole application to work with Observables, so I would need something like this: Promise -> Observable -> Promise Anyone managed to do something like this? None of the examples I've found do exactly that. I know that RxJs provides a way to make an Observable from Promise and then convert it back to Promise, but haven't figured

问题 How to invoke a method when all the observers have unsubscribed from a subject. Update const alphaStore = new BehaviourSubject(0); observer1 = alphaStore.subscribe(console.log); observer2 = alphaStore.subscribe(console.log); And when all of these observers unsubscribe. I want a method to be invoked. Like... Observer1 unsubscribed Observer2 unsubscribed All observers left 回答1: What you describe already does the finalize() operator. Better said finalize() calls its callback when the chain

问题 I have a service which loads some data in it's constructor with an Observable. Then at some later time the data can be retrieved with a getter. It should return the data right away if it's present. Or wait for loading to finish if that's still in progress. I came up with following example (code is in Typescript): class MyService { private loadedEvent = new Subject<any>(); private loaded = false; private data: any; constructor( private dataService: DataService ) { this.dataService.loadData()