has-role.guard.ts

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

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

  canActivate(
    next: ActivatedRouteSnapshot,
    state: RouterStateSnapshot): Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | UrlTree {
        const role = next.data.role;
        const user = this.authService.user();
        const idx = user.roles.findIndex(r => r === role);

        if (idx >= 0) {
          return true;
        }

        return this.router.createUrlTree(['unauthorized']);
  }
}