services, factories and providers in modern Angular

service, factory and provider all become one thing: a class marked with @Injectable.

app.factory('UserService', function ($http) {
  return {
    getAll: function () { return $http.get('/api/users'); }
  };
});

@Injectable({ providedIn: 'root' })
export class UserService {
  private http = inject(HttpClient);

  getAll() {
    return this.http.get<User[]>('/api/users');
  }
}

What changes

• providedIn: 'root' registers the service once for the whole app, like AngularJS singletons.
• Dependencies are requested with inject() and checked by TypeScript.
• constant and value become injection tokens or plain exported constants.

Related

• ui-router / ngRoute
• $stateChangeStart / transition hooks
• $timeout / $apply / $digest
• filters