import 'rxjs/add/operator/filter';

import 'rxjs/add/operator/map';

import 'rxjs/add/operator/mergeMap';

import { Component, OnInit } from '@angular/core';

import { Router, NavigationEnd, ActivatedRoute } from '@angular/router';

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

@Component({...})

export class AppComponent implements OnInit {

  constructor(

    private router: Router,

    private activatedRoute: ActivatedRoute,

    private titleService: Title

  ) {}

  ngOnInit() {

    this.router.events

      .filter(event => event instanceof NavigationEnd)

      .map(() => this.activatedRoute)

      .map(route => {

        while (route.firstChild) route = route.firstChild;

        return route;

      })

      .filter(route => route.outlet === 'primary')

      .mergeMap(route => route.data)

      .subscribe((event) => this.titleService.setTitle(event['title']));

  }

}