ngOnInit()
I created combineLatest and works perfectly, the pipe is only on "MyWebServiceWithPossibleError" to prevent the observable (combineLatest) from closing in case of error, the problem is that I don't know how to combine my observable with the web example, any help? thx
combineLatest([
Observable_One,
Observable_Two,
Observable_Three,
]).pipe(
switchMap(([R1, R2, R3]) =>
this.MyWebServiceWithPossibleError(...)
.pipe(catchError(() => { return EMPTY }))))
Web example
export enum ObsevableStatus {
SUCCESS = 'Success',
ERROR = 'Error',
LOADING = 'Loading',
}
export interface ObservableWithStatus<T> {
status: string;
data?: T;
error?: Error;
}
export function observableWithStatus<T>(x: Observable<T>): Observable<ObservableWithStatus<T>> {
return x.pipe(
map(x => ({ status: ObsevableStatus.SUCCESS, data: x })),
startWith({ status: ObsevableStatus.LOADING }),
catchError(x => {
return of({ status: ObsevableStatus.ERROR, error: x });
})
);
}
tap(()=> statusSubject.next(loading)),
map(accounts => {
return accounts.map(account => {
if (account.productType === AccountSummaryJO.ProductTypeEnum.FRUITS) {
return this.store.pipe(select(fromFruits.getFruit(account.fruitId), take(1)));
} else {
return observableOf(account)
}
})
}),
combineAll(),from + concatMap + toArray
Hi all.
So, observables are lazy, which means they don’t have the built-in caching that promises have.
So let’s say I need to request two resources from the server, then when they arrive execute a function that uses the two results.
Let’s also say that I’m going to repeat that request, but this time I can reuse one of those earlier results to save an HTTP call.
With promises this is trivial, but I’m not seeing an intuitive-looking way to do this with observables. I assume this is a fairly common thing … is there a widely-used pattern for such things?
Thank you in advance!
const foo = ["alpha", "bravo", "charlie"]
// With these types below
const fooObj = foo.reduce((acc, curr) => /* convert to object */)
/*
But fooObj now has type of
= {
alpha,
bravo,
charlie
}
*/
Hi,
I'm using rxjs in an angular application, which is chaining several combineLatest() observables.
The source observable finishes with a share() (so that the observable is replayed to new subscribers?)
The trouble I'm having is that when I subscribe to the observable in my component I am not seeing extra values that are being added via one of the many combinedLatest calls. The values appear to be in the chain of commands. I log them via tap, however my the output from my subscription appears in the console boefore those log messages and doesn't appear to include the values I suggest should be there.
my code is something like this
obs1$ = obs$.pipe(
map( /* some operation */),
share()
)
obs2$ = combineLatest(
[$obs1, $actionx] )
.pipe(
map(/* reduce the data some way*/)
)
obs3$ = combineLatest(
[ obs2$, newdata$])
.pipe(
map(/*insert new data*/)
)
obs3$.subscribe(data => this.myappdata = data)My current thoughts are that it does seem as though I'm overusing combine latest, what other appraoches can I use and then does the original share() affect when the subscribe reacts?
Shouldnt
from([])only result in completion? Seems like it just freezes
yes should be same as EMPTY
I posted the question on stackoverflow: https://stackoverflow.com/questions/64496237/rxjs-parallel-http-call-to-paginated-api-using-nestjs-httpservice
It have bountied for 50 reputation point, i got stuck on this batching task
docs say that "The output Observable only completes once all input Observables have completed" - so why does it complete?