After all these awesome answers, I hope my answer finds someone and helps them out. I wrote a small service to keep track of route history. Here it goes.

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

@Injectable()
export class RouteInterceptorService {
  private _previousUrl: string;
  private _currentUrl: string;
  private _routeHistory: string[];

  constructor(router: Router) {
    this._routeHistory = [];
    router.events.subscribe((event: any) => {
      this._setURLs(event);
    });
  }

  private _setURLs(event: any) {
    if (event instanceof NavigationEnd) {
      const tempUrl = this._currentUrl;
      this._previousUrl = tempUrl;
      this._currentUrl = event.urlAfterRedirects;
      this._routeHistory.push(event.urlAfterRedirects);
    }
  }

  get previousUrl(): string {
    return this._previousUrl;
  }

  get currentUrl(): string {
    return this._currentUrl;
  }

  get routeHistory(): string[] {
    return this._routeHistory;
  }
}

After all these awesome answers, I hope my answer finds someone and helps them out. I wrote a small service to keep track of route history. Here it goes.

import { Injectable } from '@angular/core';
import { NavigationEnd, Router } from '@angular/router';
import { filter } from 'rxjs/operators';

@Injectable()
export class RouteInterceptorService {
  private _previousUrl: string;
  private _currentUrl: string;
  private _routeHistory: string[];

  constructor(router: Router) {
    this._routeHistory = [];
    router.events
      .pipe(filter(event => event instanceof NavigationEnd))
      .subscribe((event: NavigationEnd) => {
        this._setURLs(event);
      });
  }

  private _setURLs(event: NavigationEnd): void {
    const tempUrl = this._currentUrl;
    this._previousUrl = tempUrl;
    this._currentUrl = event.urlAfterRedirects;
    this._routeHistory.push(event.urlAfterRedirects);
  }

  get previousUrl(): string {
    return this._previousUrl;
  }

  get currentUrl(): string {
    return this._currentUrl;
  }

  get routeHistory(): string[] {
    return this._routeHistory;
  }
}