observable

问题 I have followed the tutorial for angular 2 and have a search functionality that renders a list of heroes asynchronously. <div *ngFor="let hero of heroes | async"> {{hero.name}} </div> In the component I have observable heroes: heroes: Observable<Hero[]>; Now I have implemented similar functionality in my application by I don't see anything and I don't see any errors either. I opened the debugger in Chrome and tried to check the value of heroes, but it's just some Observable wrapper of course.

问题 so i am trying to figure out a way to debouce window:resize events using observables, so some kind of function would be called only after user stoped resizing window or some time has passed without size change (say 1sec). https://plnkr.co/edit/cGA97v08rpc7lAgitCOd import {Component} from '@angular/core' @Component({ selector: 'my-app', providers: [], template: ` <div (window:resize)="doSmth($event)"> <h2>Resize window to get number: {{size}}</h2> </div> `, directives: [] }) export class App {

问题 I have implemented a if statement like this if (this.service.check() ) { return true; } else { } this if condition waits for a response from the backend. But before the observable gets executed it's going into the else statement and finishing the condition without checking the if condition at start. this is my observable method to get the data from backend public check(){ this.getActorRole().subscribe( (resp => { if (resp == true){ return true } }), (error => { console.log(error); }) ); } }

问题 I have implemented a if statement like this if (this.service.check() ) { return true; } else { } this if condition waits for a response from the backend. But before the observable gets executed it's going into the else statement and finishing the condition without checking the if condition at start. this is my observable method to get the data from backend public check(){ this.getActorRole().subscribe( (resp => { if (resp == true){ return true } }), (error => { console.log(error); }) ); } }

问题 I am trying Angular2. I noticed that the http service use Observable object instead of Promise (I don't like much that choice.. async / await are arriving). In my service, I download a list of Plants from the webservice. Clicking on a plant I show the details using the routing. But in this way when I go back, the plants are downloaded again (because the constructor is called again). To avoid this I want to do something like: public getPlants(): Observable<Plants[]> { if (this._plants != null)

问题 I have a service, what is used several times from a lot of my Angular 2 components. It fetches customer data from a Web API and returns an Observable: getCustomers() { return this.http .get(this.baseURI + this.url) .map((r: Response) => { let a = r.json() as Customer[]; return a; }); } I inject this service in my root component, and in every component that wants to access the customers I just subscribe to that Observable: this.customerService.getCustomers().subscribe(v => this.items = v);

问题 I am wondering if it is possible with knockoutjs to pass arguments when binding. I am binding a list of checkboxes and would like to bind to a single computed observable in my viewmodel. In my viewmodel (based on parameter passed to the read function) I want to return true/false based on certain conditions. var myViewModel=function(){ this.myprop=ko.computed({read: function(){ //would like to receive an argument here to do my logic and return based on argument. } }); }; <input type="checkbox"

问题 It looks like there are several similar questions but after several days I do not find the proper answer. My question is how to know if the server has closed the websocket and how to try to reconnect. I have seen several examples but none of them worked properly when I wanted to implement the fonctionality of closing the websocket from the client when I change the view. Then I found this example which it's the best one I have seen so far, and with a small modifications I was able to add a

问题 I am subscribing to get user chats and then for each chat, I am subscribing to two other observables. get_user_chat(chat) { let user = this.firebase.get_user_by_uid(chat.key).snapshotChanges(); let chatInfo = this.firebase.get_single_chat(chat.payload.val()).snapshotChanges(); return Observable.forkJoin(user.take(1), chatInfo.take(1)); } getChats() { //start loading let loading = this.loadingCtrl.create(); loading.present(); //get chats this.firebase.get_user_chats().snapshotChanges()

问题 I have a component that displays a filtered list of items. It is subscribed to two observables - the first one is for (filter) parameters that need to be passed into the second observable to get the filtered list of items. public filteredItems = []; this.myService.getFilterParams() .subscribe(params => { this.myService.getFilteredItems(params) .subscribe(items => { this.filteredItems = items}); }); I've read that chaining subscribtion is not the best practice (the code works fine otherwise),