RomainMarecat/slate

import { NavigationEnd, Router } from '@angular/router';
import { Injectable } from '@angular/core';
import { filter } from 'rxjs/operators';
 
@Injectable({
  providedIn: 'root'
})
export class RoutingState {
  private history = [];
 
  constructor(private router: Router) {
  }
 
  public loadRouting(): void {
    this.router.events
      .pipe(filter(event => event instanceof NavigationEnd))
      .subscribe(({urlAfterRedirects}: NavigationEnd) => {
        this.history = [...this.history, urlAfterRedirects];
      });
  }
 
  public getHistory(): string[] {
    return this.history;
  }
 
  public getPreviousUrl(): string {
    return this.history[this.history.length - 2] || '/';
  }
}