How to intercept a cancelled http request in Angular?

Question

Angular cancels http requests very fast and I want to intercept those cancelled requests. Is it possible to capture cancelled requests in the interceptor? Below is a fragment of my interceptor code, where I want to catch cancelled request.

  intercept(req: HttpRequest<any>, next: HttpHandler): 
Observable<HttpEvent<any>> {
    this.onStartRequest();
    // Pass the cloned request instead of the original request to the next handle
    return next.handle(req).do(
      (event: HttpEvent<any>) => {
        if (event instanceof HttpResponse) {
         // do something
        }
      },
      (err: any) => {
        if (err instanceof HttpErrorResponse) {
          // do something
        }
      }
    );
  }

Answer 1

You have to use the catchError RxJs operator when you use the next Handler, here's the code:

intercept(req: HttpRequest<any>, next: HttpHandler): 
Observable<HttpEvent<any>> {
    this.onStartRequest();
    // Pass the cloned request instead of the original request to the next handle
    return next.handle(req).do(
      (event: HttpEvent<any>) => {
        if (event instanceof HttpResponse) {
         // do something
        }
      })
      .catchError((err: HttpErrorResponse) => {
        // Handle errors
      });
  }

PS: Don't forget to import the catchError operator.

Answer 2

Did you try with the finalize event?

return next.handle(req).pipe(
  finalize(() => {
    // request completes, errors, or is cancelled
  })
);