root direction in angular code example

Example 1: angular on back skip routes

this.router.navigate(["/c"], { replaceUrl: true });

Example 2: how to add changes every time you route navigate to page in angular

// Place import at the top
import { Router,NavigationStart} from '@angular/router';

//Place the code below inside your class
constructor(private router: Router){}

ngOnInit(){
   this.router.events.subscribe(event =>{
      if (event instanceof NavigationStart){
   		
      }
   })
}