Catch in Observable stops HTTP Calls from Observable.interval

问题

Observable.interval(10000)
     .switchMap(() => this.http.get(url))
     .catch (err => Observable.empty())
     .subscribe(data => render(data))

Each 10 seconds we make an HTTP call. If an error happens, observable becomes completed, it doesn't make any calls anymore. How to prevent that?

回答1:

That's correct behavior, when a complete or error notification is sent observers unsubscribe and the chain is disposed.

You can use the retry() operator to resubscribe but it's hard to tell what is your goal from this brief description.

Observable.interval(10000)
    .switchMap(() => this.http.get(url))
    .retry()
    .subscribe(data => render(data))

回答2:

takeUntil() of observable.

RxJS implements the takeUntil operator. You can pass it either an Observable or a Promise that it will monitor for an item that triggers takeUntil to stop mirroring the source Observable.

for more info click here

回答3:

Try this:

let dataX = Observable.interval(10000)
 .switchMap(() => this.http.get(url));

let caught = dataX.catch(
Observable.return({
error: 'There was an error in http request'
}))

caught.subscribe((data) => { return render(data) },
// Because we catch errors now, `error` will not be executed
(error) => {console.log('error', error.message)}
 )

if you want you can put any condition when the error comes like

if(!data[error]){
  render(data)
}

I hope that it helps you

回答4:

Observable.interval(10000)
     .switchMap(() => this.http.get(url)
     .map(res => res.json())
     .catch (err => Observable.empty()))
     .subscribe(data => render(data))

来源：https://stackoverflow.com/questions/45715543/catch-in-observable-stops-http-calls-from-observable-interval

标签

javascript

angular

rxjs

observable