matsen-tool-fe/matsen-tool/src/app/_helpers/auth.guard.ts

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

import { AccountService } from '@app/_services';

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

    canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot) {
        const user = this.accountService.userValue;
        if (user) {
            // authorised so return true
            return true;
        }

        // not logged in so redirect to login page with the return url
        this.router.navigate(['/account/login'], { queryParams: { returnUrl: state.url }});
        return false;
    }
}