how to route with in screen in angular 7 code example

Example 1: add component in angular router

First you need to make component using 'ng generate'
$ ng generate component home
$ ng generate component about

Next, in the src/app/app-routing.module.ts file import the components as follows:

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';

import { HomeComponent } from './home/home.component';
import { AboutComponent } from './about/about.component';
Next, add the routes as follows:

const routes: Routes = [
  { path: 'home', component: HomeComponent },
  { path: 'about', component: AboutComponent }

];
So now if you visit the /home path you should go to home component and if you visit the /about path you should go to the about component.
/*
I hope it will help you.
Namaste
Stay Home Stay Safe
*/

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){
   		
      }
   })
}