<app-navbar></app-navbar>

<router-outlet></router-outlet>

<mat-toolbar color="primary" class="mat-elevation-z8">

    <span><mat-icon>euro_symbol</mat-icon> Rechnungen</span>

    <div class="spacer"></div>

    <a mat-button router-link="/customers">Kunden</a>

    <a mat-button router-link="/articles">Artikel</a>

    <a mat-button router-link="/invoices">Rechungen</a>

</mat-toolbar>

import { NgModule } from '@angular/core';

import { RouterModule, Routes } from '@angular/router';

import { CustomersComponent } from './customers/customers.component';

import { InvoicesComponent } from './invoices/invoices.component';

import { ArticlesComponent } from './articles/articles.component';

const routes: Routes = [

  {path: 'invoices', component:InvoicesComponent},

  {path: 'articles', component:ArticlesComponent},

  {path: 'customers', component:CustomersComponent}

];

@NgModule({

  imports: [RouterModule.forRoot(routes)],

  exports: [RouterModule]

})

export class AppRoutingModule { }

import { NgModule } from '@angular/core';

import { BrowserModule } from '@angular/platform-browser';

import { AppRoutingModule } from './app-routing.module';

import {MatToolbarModule} from '@angular/material/toolbar';

import {MatButtonModule} from '@angular/material/button';

import {MatIconModule} from '@angular/material/icon';

import { AppComponent } from './app.component';

import { BrowserAnimationsModule } from '@angular/platform-browser/animations';

import { NavbarComponent } from './navbar/navbar.component';

import { ArticlesComponent } from './articles/articles.component';

import { InvoicesComponent } from './invoices/invoices.component';

import { CustomersComponent } from './customers/customers.component';

@NgModule({

  declarations: [

    AppComponent,

    NavbarComponent,

    ArticlesComponent,

    InvoicesComponent,

    CustomersComponent

  ],

  imports: [

    BrowserModule,

    AppRoutingModule,

    BrowserAnimationsModule,

    MatToolbarModule, //import mattoolbar 

    MatButtonModule,

    MatIconModule

  ],

  providers: [],

  bootstrap: [AppComponent]

})

export class AppModule { }