Angular -无法读取catchError中的www-authenticate头

import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpRequest, HttpHandler, HttpEvent } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { catchError } from 'rxjs/operators';

@Injectable()
export class AuthInterceptor implements HttpInterceptor {
  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    return next.handle(request).pipe(
      catchError(error => {
        if (error.status === 401) {
          const wwwAuthenticateHeader = error.headers.get('www-authenticate');
          // 在这里处理www-authenticate头
          console.log(wwwAuthenticateHeader);
        }
        return throwError(error);
      })
    );
  }
}