错误 TS2769：没有重载匹配此调用。键入'字符串 | null' 不可分配给类型 'string |细绳[]'答案

【问题标题】：error TS2769: No overload matches this call. Type 'string | null' is not assignable to type 'string | string[]'错误 TS2769：没有重载匹配此调用。键入'字符串 | null' 不可分配给类型 'string |细绳[]'
【发布时间】：2023-03-28 04:07:01
【问题描述】：

export class AuthService {

  constructor(private http: HttpClient, private webService: WebRequestService, private router: Router) { }

  login(email: string, password: string) {
    return this.webService.login(email, password).pipe(
      shareReplay(),
      tap((res: HttpResponse<any>) => {
        // auth tokens will be in the header of this response 
        this.setSession(res.body._id, res.headers.get('x-access-token'), res.headers.get('x-refresh-token'));
        console.log('logged in');
      })
    )
  }

  logout() {
    this.removeSession();
    this.router.navigate(['/login']);
  }

  getAccessToken() {
    return localStorage.getItem('x-access-token');
  }

  getRefreshToken() {
    return localStorage.getItem('x-refresh-token');
  }

  getUserId() {
    return localStorage.getItem('user-id');
  }

  setAccessToken(accessToken: any) {
    return localStorage.setItem('x-access-token', accessToken);
  }

  private setSession(userId: string, accessToken: any, refreshToken: any) {
    localStorage.setItem('user-id', userId);
    localStorage.setItem('x-access-token', accessToken);
    localStorage.setItem('x-refresh-token', refreshToken);
  }

  private removeSession() {
    localStorage.removeItem('user-id');
    localStorage.removeItem('x-access-token');
    localStorage.removeItem('x-refresh-token');
  }

  getNewAccessToken() {
    return this.http.get(`${this.webService.ROOT_URL}/users/me/access-token`, {
      headers: {
        'x-refresh-token': this.getRefreshToken(),
        '_id': this.getUserId()
      },
      observe: 'response'
    }).pipe(
      tap((res: HttpResponse<any>) => {
        this.setAccessToken(res.headers.get('x-access-token'));
      })
    )
  }
}

【问题讨论】：

标签： angular typescript

【解决方案1】：

阅读存储文档时，您可以看到 Storage.getItem('') 返回 string 或 null (see here)。使用您的代码，我假设您在 Angular 和文档中工作，HttpClient headers 对象可以是 string | string[] (see here)，因此与类型存在冲突。

也许您可以尝试这样的方法来修复错误：

getRefreshToken(): string {
    return localStorage.getItem('x-refresh-token') || '';
 }

【讨论】：