Route Guards

// auth.guard.ts
import { Injectable } from '@angular/core';
import { CanActivate, Router, ActivatedRouteSnapshot } from '@angular/router';

@Injectable({ providedIn: 'root' })
export class AuthGuard implements CanActivate {
  
  constructor(private authService: AuthService, private router: Router) {}
  
  canActivate(route: ActivatedRouteSnapshot): boolean {
    if (this.authService.isLoggedIn()) {
      return true;  // Allow access
    }
    
    // Redirect to login
    this.router.navigate(['/login']);
    return false;
  }
}

// app-routing.module.ts
const routes: Routes = [
  { 
    path: 'admin', 
    component: AdminComponent,
    canActivate: [AuthGuard]  // Protected route
  },
  { path: 'login', component: LoginComponent }
];

// Other guards:
// canDeactivate - prevent leaving a page
// canLoad - prevent lazy loading
// canActivateChild - protect child routes