Questions tagged [rxjs-observables]
759 questions
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1 answer
Angular firestore get document field as string
I know there is a ton of questions like this, but none of the solutions solve my problem.
IVe been stuck on this for a while, and would really appreciate some help/guidance.
I suppose there is something big I am missing in the ideas of observable,…
breadman0
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4 answers
How to extract only certain properties of json, returning as an observable using rxjs
For example this is the json which I am receiving,
{
"events": [...
],
"total": 12341,
"students": [
{
"id": 1,
"first_name": "John",
"last_name": "Apple"
},
{
…
pepega
- 25
- 8
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1 answer
Rxjs Subject not emitting data immediately
I have a service with a RXJS subject and i am assigning data to subject inside constructor doing an api call. This subject I am subscribing in a component template. Though the data is provided to the subject, it is not emitting immediately the first…
Niranjan
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angular subscribe to changes only if previous value of the form control !== currentvalue of the formcontrol
I would like to call onDataChange() only if previous value of input / selection != current Value of input / selection.
However I've noticed that it is still calling onDataChange() whenever put the cursor on the input field (but didn't change any…
user21
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2 answers
Unsubscribe to observable when navigating away from an onsen ui page
I have an angular 2+ app running onsen ui, I have setup some components as pages and I am using the ons-navigator to switch between them.
The problem im having is that when im subscribed to an observable in an ons-page and the user navigates away…
SanzioSan
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1 answer
Is there a way to perform static code analysis/linting for Angular memory leak?
Let's say the proper pattern in Angular to unsubscribe from an observable in a component is thus:
Now let's say I forgot the .unsubscribe() call in ngOnDestroy(). Is there any linting rule I could set up to catch this, or it must strictly rely on…
Alex. A
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rxjs: load many for many from 2 endpoints and merge into single Observable
I have one endpoint for getting list of users, and another for getting list of apartments for every user:
getUsers() => Observable;
getUserApartments(userId) => Observable`
How do I merge the data from the two into single…
eagor
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1 answer
RxJS Overwrite Timer/Observable Best Practice
I am trying to "reset" a timer when a service emits a new Expiration time. I have it overwriting the observable. I am not sure if i should "garbage collect" the observable OR if there is a better way to "reset" the timer.
This code works fine but i…
Ricardo Saracino
- 1,345
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can i bind from event to custom component output
i am having a custom component
export class SystemInputComponent implements OnInit, OnDestroy {
@Input() ...
@Output() enterFn: EventEmitter = new EventEmitter();
...
that has output that act as an event as i know
and that…
Hassan Ahmed
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3 answers
Angular with RxJS - Array's Reduce Function Not Working When Subscribed To An Observable
I have the following code and I'm trying to calculate the total of all items added to the cart. When I use reduce I don't get back anything but while troubleshooting I added a map in there (commented out code) and that prints a value. I can add more…
sayayin
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1 answer
Angular - How To Process an Observable in the Class
New to Angular. Wanted to learn how to manage state centrally so used ngRx. Also, have not used an Observable before so I am really stuck. Below is my code where the cart holds and array of objects. I just need to iterate over the cart which is…
sayayin
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1 answer
How to retrieve last value passed to next() of an Rxjs Observable outside the observer
I have a class with more than 30 observable attributes. Each time my server receives a payload containing these 30 attributes I call the next() method for all the corresponding attributes of the instance, so far so good.
The problem is that,…
Teodoro
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2 answers
Unhandled Promise rejection: You provided 'undefined' where a stream was expected. Using SwitchMap and a function of type Observable
this is my first time using switchMap from the rxjs library.
Im guessing this error message means its unhappy with how I am doing things.
Observe my addemail function
addemail(form:NgForm){
…
user14150478
1
vote
2 answers
Chain Observable RxJs in Angular
I use RxJs 6.6.0 and Angular 9.
I have two functions which returns Observable<'Class1'> and Observable<'number'>.
so I use to:
funcA().subscribe(x=>{ // do something...});
funcB().subscribe(x=>{// do somethings..});
But I need to call funcB only…
Arno
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2 answers
