auth.ts

export class AuthService {
  private readonly createRequest: AjaxCreationMethod = this.config.createRequest;
  private readonly refreshToken$ = this.refreshToken();

  constructor(private readonly config: AuthServiceConfig) {}

  authenticate(username: string, password: string): Observable<AjaxResponse> {
    return this.createRequest({
      url: '/account/login',
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: {
        username,
        password,
      },
    });
  }

  refreshToken(): Observable<boolean> {
    return this.createRequest({
      url: '/account/refresh_token',
      method: 'POST',
    }).pipe(
      catchError(() => of(false)), // refresh failed
      mapTo(true), // refresh success!
      share(), // merge subscribers and share results
    );
  }

  attemptTokenRefreshOn401() {
    return <T>(source: Observable<T>): Observable<T> =>
      source.pipe(
        catchError((err, caught) => {
          if (err.status === 401) {
            return this.refreshToken$.pipe(mergeMap(() => caught)); // refresh then retry
          }
          return caught; // retry
        }),
      );
  }

  // Like regular ajax(), but attempts an auth refresh on
  // 401 and then sets the authStatus subject appropriately
  ajax(params: AjaxRequest): Observable<AjaxResponse> {
    const ajax$ = this.createRequest(params);
    const ajaxWithReauth$ = ajax$.pipe(this.addAutoReauth());
    return ajaxWithReauth$;
  }
}