Rxjs将超时错误从管道抛出到可观察到的错误部分

Question

I'm trying to throw timeout error from the observable pipe to the observer as an error but I am still getting the timeout error in the val callback (in subscribe) while I want to get it in the error callback:

For who is experimented, you can test this code easly and edit it in stackblitz in this link:

https://stackblitz.com/edit/typescript-eegqyz?file=index.ts&devtoolsheight=100

of(4000, 3000, 2000)
    .pipe(
        concatMap(duration =>
            makeRequest(duration).pipe(
                timeout(2500),
                catchError(error => {
                    //throwError('Valid token not returned');
                    return of(`Request timed out after: ${duration}`)
                })
            )
        )
    )
    .subscribe(
        val => console.log(val),
        error => console.log("error", error)
    );

Answer 1

Here's how I managed to solve it:

of(4000, 3000, 2000)
  .pipe(
    concatMap(duration =>
      makeRequest(duration).pipe(
        timeout(2500),
        catchError(err => throwError(`Request timed out after: ${duration}`))
      )
    ),
  )

So, basically you have a way to handle errors that come from timeout (which is why you were getting the error in the first cb from subscribe() ) and now if throw another error(using throwError ), there is no other place to handle the incoming errors, so you will get the error in its callback(from subscribe() ).

Here is a StackBlitz example .