src/app/dialogs/logout/logout.component.ts

import { Component, Optional } from '@angular/core';
import { MdDialogRef } from '@angular/material';
import { MessageService, MessageDefines } from '../../services/message.service';
import { AuthenticationService } from '../../services/authentication.service';
import { Router } from '@angular/router';

@Component({
  selector: 'app-logout',
  templateUrl: './logout.component.html',
  styleUrls: ['./logout.component.css'],
})
export class LogoutComponent {

  constructor(
    @Optional() public dialogRef: MdDialogRef<LogoutComponent>,
    private msgService: MessageService,
    private authService: AuthenticationService,
    private router: Router) {}

  logout() {
    this.authService.logout().subscribe(res => {      
      this.dialogRef.config.data.logout();
      this.msgService.loginLogoff$.emit(MessageDefines.MSG_LOG_OFF);
      this.dialogRef.close();
      this.router.navigate(['/logout']);      
    },
      error => { 
        console.log(error);
      }
    );    
  }
}