Angular 6 router.events.filter 'filter' does not exist on type 'Observable<Event>'

This is how to filter router events with Angular 6+ and latest RxJS:

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

import { filter } from 'rxjs/operators';

export class MyComponent implements OnInit {
    constructor(private router: Router, private activatedRoute: ActivatedRoute) {}

    ngOnInit() {
        this.router.events.pipe(
            filter(event => event instanceof NavigationEnd)
        ).subscribe(() => {
            console.log(this.activatedRoute.root);
        });
    }
}

Uses the pipe operator instead of attempting to chain filter on the observable.

I don't see in your code if you imported filter

for Rxjs 6:

import { filter } from 'rxjs/operators';

    .
    .
    .

     this.router.events.pipe(
       filter((event:Event) => event instanceof NavigationEnd)
     ).subscribe(res => console.log(res))