I want to check if the request is timeout when I send a request to the port. I just want to print an error when the request is timeout.

myService.service.ts

checkStatus() : Observable<any> {
    return this.http.get<any>('http://127.0.0.1:3001'); // simple example
}

myComponent.ts

this.myService.checkStatus.subscribe(() => {}, 
  (err) => {
     // if the timeout error is print error
  }
}

I just want the error to be removed from the screen when the timeout error is fixed. if error 404 or a different error returns, I do not want the operation to be performed and printed to screen.

in short, it is as follows

1. A request will be sent to the port and checked for a timeout error.
2. If there is a timeout error, an error will be printed on the screen.(404 or different errors will not print, only timeout error)
3. if there is a timeout error, it will be checked if the error persists, and if the error does not occur, the text on the screen will be removed.

CodePudding user response：

You can do something like this, to catch your error.

this.myService.checkStatus
  .pipe(
     catchError(error) => // do something with it)
   )
  .subscribe(yourResponse => // handle your response)

CodePudding user response：

Using retryWhen to check timeOut error with certain interval,and which is here a inner observable,and outer observable only to emit mesages for ui

myService.service.ts

  checkStatus() : Observable<any> {
    return Observable.create((observer) => {
      this.http
        .get<any>('http://127.0.0.1:3001')
        .pipe(
          retryWhen((err) => {
            return err.pipe(
              switchMap((err, i) => {
                
                // If it is a time out error,
                // then emit message to display
                // and set next retry attempt
                // by returning timer observable
               
                if(err.status === 504){
                   observer.next("timeout error!");
                   return timer(2000);
                } else{

                   // If it's not a timeout error
                   // then return null or anything you want
                   // On basis of what you can remove message 
                   // from ui

                   observer.next(null);
                }
                throwError(() => 'sorry!');
              })
            );
          }),
          catchError((err) => {
            return throwError(err);
          })
        )
        .subscribe(console.log);
    });
  }

myComponent.ts

this.myService.checkStatus.subscribe(
  (res) => {
     // if the timeout error is print error
  }, 
  (err) => {
    
  }
}