Angular2 rxjs - switchmap 捕获错误

Question

我希望能够处理调用this.authService.refreshToken() 时出现的任何错误。是否可以在 switchmap 块中处理错误，或者在这种情况下如何处理错误？

post3(endpoint: string, body: string) : Observable<any> {
    if (this.authService.tokenRequiresRefresh()) {
      this.authService.tokenIsBeingRefreshed.next(true);
      return this.authService.refreshToken().switchMap(
        data => {
          this.authService.refreshTokenSuccessHandler(data);
          if (this.authService.loggedIn()) {
            this.authService.tokenIsBeingRefreshed.next(false);
            return this.postInternal(endpoint, body);
          } else {
            this.authService.tokenIsBeingRefreshed.next(false);
            this.router.navigate(['/sessiontimeout']);
            Observable.throw(data);
          }
        }
      );
    }
    else {
      return this.postInternal(endpoint, body);
    }
  }

Answer 1

使用catchError 方法

this.authService.refreshToken()
  .pipe(
     switchMap(() => {...}),
     catchError((e) => {
       // handle e and return a safe value or re-throw
       if (isCritical(e)) {
         return throwError(e);
       }
       return of([]);
    })
  );