angular - HttpInterceptor 中的注入(inject)服务未初始化

Question

我正在尝试将服务注入(inject) HttpInterceptor，这是简单的服务

import { Injectable } from '@angular/core';
@Injectable()
export class LoginLoadingService {
   constructor() { }
   public loaded: boolean;
   isLoaded() {
       if (this.loaded === undefined) {
             this.loaded = true;
       }
       return this.loaded;
  }    
}

拦截器

import { HttpRequest, HttpHandler, HttpEvent, HttpInterceptor } from 
'@angular/common/http';
import { Injectable, Inject } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import { LoginLoadingService } from './loading.service';
import 'rxjs/add/operator/do';
@Injectable()
export class LoginLoadingInterceptor implements HttpInterceptor {
  constructor(public loginLoadingService: LoginLoadingService) { }
  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    this.loginLoadingService.loaded = false
    return next.handle(req).do((event: HttpEvent<any>) => {
      this.loginLoadingService.loaded = true;
    }, error => console.error(error));
  }
}

在我的 app.module 中

providers: [
  LoginLoadingService,
  {
    provide: HTTP_INTERCEPTORS,
    useClass: LoginLoadingInterceptor,
    multi: true
  }
]

HttpInterceptor 运行正常，但 loginLoadingService 未在 intercept() 方法中定义。我试图将 deps 添加到 app.module 中的拦截器，但这给了我这个错误

params.map is not a function

不知道是什么问题

Answer 1

像下面这样定义拦截器的依赖关系:

例如，我们有AuthInterceptor，我们注入(inject)了LocalStorageService和SessionStorageService。

在 app.module.ts 中我们添加拦截器 AuthInterceptor :

   {
        provide: HTTP_INTERCEPTORS,
        useClass: AuthInterceptor,
        multi: true,
        deps: [LocalStorageService, SessionStorageService]
    },

这会起作用。