angular - 当我提供拦截器时获取 'Can' t 解析所有参数

Question

我正在尝试实现 HttpInterceptor。当我将它添加到@NgModule 时，我在 Chrome 中收到以下错误:

Uncaught Error: Can't resolve all parameters for JwtInterceptor: (?, ?).
    at syntaxError (compiler.js:466)
    at CompileMetadataResolver._getDependenciesMetadata (compiler.js:15547)
    at CompileMetadataResolver._getTypeMetadata (compiler.js:15382)

花了很多时间在 google 上，不知道该做什么......

这是我在 AppModule 中提供拦截器的方式:

...
providers: [
   {
      provide: HTTP_INTERCEPTORS,
      useClass: JwtInterceptor,
      multi: true
   }
],
...

这是拦截器本身，没什么特别的:

export class JwtInterceptor implements HttpInterceptor {
   constructor(private inj: Injector, private logger: Logger) {
      this.logger.l(true)('Interceptor >>');
   }

   intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
      this.logger.l(true)('interceptor >>');

      const auth = this.inj.get(AuthService);

      // add token to the request:
      const authReq = req.clone({
         setHeaders: {
            Authorization: `Bearer ${auth.getToken()}`
         }
      });

      // return next.handle(authReq);
      return next.handle(authReq).do((event: HttpEvent<any>) => {
         if (event instanceof HttpResponse) {
            // todo: get refreshed token if it exists:
         }
      }, (err: any) => {
         if (err instanceof HttpErrorResponse) {
            if (err.status === 401) {
               auth.collectFailedRequest(authReq);
               // todo: redirect to the login route or show a modal
            }
         }
      });
   }
}

Answer 1

糟糕，我忘了将 @Injectable() 添加到我的 interceptor 类中。