在Angular应用程序中，很多时候需要在HTTP请求中添加JWT令牌。为了实现这个功能，可以使用拦截器来在每个请求中添加JWT令牌。但是，JWT令牌的有效期有限，因此我们需要通过异步操作在过期时刷新令牌。

以下是一种正确处理JWT令牌刷新的方法，可以在拦截器中使用。首先，我们需要创建一个名为TokenInterceptor的拦截器，并将其添加到providers数组中。

import { Injectable } from '@angular/core';
import {
  HttpEvent,
  HttpInterceptor,
  HttpHandler,
  HttpRequest,
  HttpErrorResponse
} from '@angular/common/http';
import { Observable, BehaviorSubject, throwError } from 'rxjs';
import { catchError, filter, take, switchMap } from 'rxjs/operators';
import { AuthService } from '../services/auth.service';

@Injectable()
export class TokenInterceptor implements HttpInterceptor {
  private isRefreshing = false;
  private refreshTokenSubject: BehaviorSubject = new BehaviorSubject(null);

  constructor(public authService: AuthService) {}

  intercept(request: HttpRequest, next: HttpHandler): Observable> {
    if (this.authService.getAccessToken()) {
      request = this.addToken(request, this.authService.getAccessToken());
    }

    return next.handle(request).pipe(
      catchError(error => {
        if (error instanceof HttpErrorResponse && error.status === 401) {
          return this.handle401Error(request, next);
        } else {
          return throwError(error);
        }
      })
    );
  }

  private addToken(request: HttpRequest, token: string) {
    return request.clone({
      setHeaders: {
        'Authorization': `Bearer ${token}`
      }
    });
  }

  private handle401Error(request: HttpRequest, next: HttpHandler) {
    if (!this.isRefreshing) {
      this.isRefreshing = true;
      this.refreshTokenSubject.next(null);

      return this.authService.refreshToken().pipe(
        switchMap((newToken: any) => {
          this.isRefreshing = false;
          this.refreshTokenSubject.next(newToken.access_token);
          return next.handle(this.addToken(request, newToken.access_token));
        }),
        catchError(err => {
          this.isRefreshing = false;
          this.authService.logout();
          return throwError(err);
        })
      );
    } else {
      return this.refreshTokenSubject.pipe(
        filter(token => token != null),
        take(1),
        switchMap(token => {
          return next.handle(this.addToken(request, token));
        })
      );
    }
  }
}

在上面的代码中