How to do dependency injection in Ember with Ember CLI? - ember.js

Question

First, I made a small Ember app without Ember CLI.
I had this piece of code.
window.MyApp = Ember.Application.create({
ready: function() {
this.register('session:current', MyApp.SessionController, { singleton: true });
this.inject('controller', 'session', 'session:current');
}
});
This worked.
Then I decided to rewrite everything from scratch with Ember CLI.
I edited the file app/app.js and added the ready hook just like in my previous version.
var App = Ember.Application.extend({
modulePrefix: config.modulePrefix,
podModulePrefix: config.podModulePrefix,
Resolver: Resolver,
ready: function() {
this.register('session:current', App.SessionController, { singleton: true });
this.inject('controller', 'session', 'session:current');
}
});
This doesn't work.
The session controller does exist. That's the content of the file app/controllers/session.js
export default Ember.Controller.extend({
isLoggedIn: false,
});
The error message I get is
TypeError: Attempting to register an unknown factory: `session:current`
It appears in the browser.
I googled that message, but I found nothing about dependency injection in Ember CLI.
Any idea?

Answer 1

In ember-cli you can use ember generate service <name of service> and ember generate initializer <name of initializer> to build the stubs to achieve this, which is far better than fiddling about with app.js.
You create a service basically like this:
// app/services/notifications.js
import Ember from 'ember';
export default Ember.Object.extend({
initNotifications: function() {
// setup comes here
}.on('init'),
// Implementation snipped, not relevant to the answer.
});
And the initializer, which injects the service into the component(s) of your application which need it:
// app/initializers/notifications-service.js
import Notifications from '../services/notifications';
export default {
name: 'notification-service',
after: 'auth-service',
initialize: function( container, app ) {
app.register( 'notifications:main', Notifications, { singleton: true } );
app.inject( 'component:system-notifications', 'notificationService', 'service:notifications' );
app.inject( 'service:auth', 'notificationService', 'service:notifications' );
}
};
With that, it becomes available as notificationService on the components specified.
Documentation on the subject of dependency injection in Ember can be found at http://emberjs.com/guides/understanding-ember/dependency-injection-and-service-lookup/