How do I implement an authentication guard in my application?

How do I implement an authentication guard in my application?

To implement an authentication guard, you can use middleware to check if a user is authenticated before accessing certain routes.

What technologies or frameworks can I use for this?

You can implement authentication guards in frameworks like Angular, React, or Express.js using their respective routing systems.

Can you provide a code example for an Angular guard?

Sure! Here's a simple Angular guard example:

import { Injectable } from '@angular/core';
import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot, Router } from '@angular/router';
import { AuthService } from './auth.service';

@Injectable({ providedIn: 'root' })
export class AuthGuard implements CanActivate {
  constructor(private authService: AuthService, private router: Router) {}

  canActivate(
    next: ActivatedRouteSnapshot,
    state: RouterStateSnapshot
  ): boolean {
    if (this.authService.isLoggedIn()) {
      return true;
    }
    this.router.navigate(['/login']);
    return false;
  }
}

What should I do if a user is not authenticated?

If a user is not authenticated, you should redirect them to a login page or show an appropriate message.