CODEWITHSUNDEEP
rxjsreactive-programming
Héctor Valls
Héctor Valls

Reputation: 26084

Emit error after timeout in RxJS

I want to emit an error if a method's execution takes more time than a defined timeout. I have tried this (ES6):

getExec() {
    return _getObs().timeout(5000, new Error("timeout reached")); //5s timeout
}

_getObs() {
    return rx.Observable.create((sub) => {
        sub.onNext(executeVerySlowMethod());
        sub.onCompleted();
    });
}

When I subcribe to getExec, it doesn't raise any error. What am I doing wrong? (executeVerySlowMethod is a really slow method that takes more than 5 secs)

Upvotes: 1

Views: 1235

Answers (2)

mrmashal
mrmashal

Reputation: 1883

This is the new way to do it: (RxJS6)

import { of, TimeoutError, throwError } from 'rxjs';
import { timeout, catchError } from 'rxjs/operators';

of(executeVerySlowMethod()).pipe(
   timeout(5000),
   catchError(err => {
      if (err instanceof TimeoutError) {
         throw new Error('timeout reached');
      }
      return throwError(err);
   }))

Upvotes: 2

Mark van Straten
Mark van Straten

Reputation: 9425

There is no overload of .timeout() available which takes a custom Error. This was removed in RxJs5. Your code will error because the second argument is expected to be of type Scheduler|null.

Also; creating an observable to wrap your function can be done easier by just using Observable.of(executeVerySlowMethod()) which is less error-prone.

Observable
  .of(executeVerySlowMethod())
  .timeout(5000)

should do the trick UNLESS executeVerySlowMethod() is blocking // sync.

Upvotes: 3

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