title: Cannot find module './auth.service' in Angular 7
body: <p>I'm trying to use Angular Guards, to protect my pages from access without being authenticated.</p>
  <pre><code>import { ActivatedRouteSnapshot, CanActivate, RouterStateSnapshot , Router } from '@angular/router';
  import { Observable } from 'rxjs';
  import { Injectable } from '@angular/core';
  import { AuthService } from './auth.service';
  @Injectable()
  export class AuthGuard implements CanActivate {
      constructor(private authService: AuthService,
          private router: Router) { }
      canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable&lt;boolean&gt; | Promise&lt;boolean&gt; | boolean {
          if(this.authService.isAuth) {
              return true;
          } else {
              this.router.navigate(['/login']);
          }   
      }
  }
  
  </code></pre>
  <p>the problem is that I can not import the module auth.service. it show me this error ( cannot find module './auth.service'. any suggestions ?</p>