Javascript 角度路由器循环依赖错误

我在Angular 5项目上有以下循环依赖错误，我不明白为什么。 当我从token.service.ts中删除路由器依赖项时，该错误已修复，但我需要它。我试图在代码中做的是在应用程序初始化期间调用一个方法 以下是我所拥有的：

app.modules.ts

import { BrowserModule } from '@angular/platform-browser';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { NgModule } from '@angular/core';
import { HttpModule } from '@angular/http';
import { HttpClientModule, HttpClient } from '@angular/common/http';
import { SearchEngineModule } from './search-engine/search-engine.module';
import { AppLoadModule } from './app-load/app-load.module';
import { AppLoadService } from './app-load/app-load.service';
import { AppComponent } from './app.component';
import { SearchService } from './search-engine/search.service';
import { AppRoutingModule } from './app-routing.module';
import { Routes, RouterModule } from '@angular/router';
import { SearchListComponent } from './search-engine/search-list/search-list.component';
import { TokenService } from './token.service';

const routes: Routes = [
  {
    path: 'searchList',
    component: SearchListComponent
  }
];

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    HttpClientModule,
    HttpModule,
    AppLoadModule,
    SearchEngineModule,
    RouterModule.forRoot(routes, { useHash: true })
  ],
  providers: [ TokenService , AppLoadService],
  bootstrap: [ AppComponent ]
})
export class AppModule { }

app-load.module.ts

import { NgModule, APP_INITIALIZER} from '@angular/core';
import { AppLoadService } from './app-load.service';
import { CommonModule } from '@angular/common';

export function init_app(appLoadService: AppLoadService) {
  return () => appLoadService.initializeApp();
}

@NgModule({
  imports: [
    CommonModule
  ],
  providers: [
    { provide: APP_INITIALIZER, 
      useFactory: init_app, 
      deps: [AppLoadService], 
      multi: true 
    }
  ],
  declarations: []
})
export class AppLoadModule { }

app-load.service.ts

import { Injectable } from '@angular/core';
import { TokenService } from '../token.service';

@Injectable()
export class AppLoadService {

  constructor(private tokenService: TokenService) { }

  initializeApp(): Promise<any> {
    return new Promise((resolve, reject) => {
      setTimeout(() => {
        this.tokenService.obtainAccessToken();
        resolve();
      }, 3000);
    });
  }
}

import { Injectable } from '@angular/core';
import { Router } from "@angular/router";
import { Cookie } from 'ng2-cookies';
import { Http, Response, Headers, RequestOptions } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/map';


@Injectable()
export class TokenService {

  constructor(private router: Router, private _http: Http) { }

  obtainAccessToken() {
    // some code
    this.router.navigate(['/']);
  }
}

有人能提出什么建议吗？ 提前谢谢