使用dart定义angular2组件的提供程序

Question

I'm writing an angular2 dart application using Intellij.

I created a provider called Auth that should be injected to the app component.

I defined the Auth service using the following code:

import 'package:angular2/core.dart';
import 'package:auth0_lock/auth0_lock.dart';
import './config.dart';

@Injectable()
class Auth {
Auth0Lock lock;

Auth() {
    this.lock = new Auth0Lock(configObj.auth0.apiKey, configObj.auth0.domain);
}
updateProfileName(data) {
  var profile = data['profile'] != null ? data['profile'] : data;
  print(profile['name']);
}

login() {
    this.lock.show(popupMode: true, options: {'authParams': {'scope': 'openid profile'}}).then(this.updateProfileName);
}
}

and the app component using the following code:

import 'package:angular2/core.dart';
import 'package:angular2/router.dart';
import 'welcome_component.dart';
import 'auth_service.dart';

@Component(
    selector: 'my-app',
    templateUrl: '/www/my-app.html',
   providers: [Auth]
)
@RouteConfig(const [
  const Route(path: '/welcome', component: WelcomeComponent, name: 'welcome')
])
class AppComponent {
  Auth auth;
  AppComponent(Auth auth) {
    this.auth=auth;
  }
}

now intellij is complaning about the providers array with the error message arguments of constant creation must be constant expressions .

I'm new to dart... but if the Component configuration needs consts, how can I provide classes to be used there ?

thanks

Answer 1

Just adding const should do:

providers: const [Auth]

The error you're seeing is because [Auth] creates a List that — although it contains only a const memeber — is itself not constant. (For example, it could be added to, or cleared.) Dart requires you to specify explicitly that the List is constant.