app-routing.module.ts

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';
import { AboutComponent } from './about/about.component';
import { HeaderComponent } from './header/header.component';
import { HelpComponent } from './help/help.component';
import { DataService } from "./data.service";

const routes: Routes = [
  {
    path: "", 
    component: HeaderComponent, 
    resolve: {
      employees: DataService
    }},
  {path: "about", component: AboutComponent},
  {path: "help", component: HelpComponent}

];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }