Access property inside Ember component

Need your help folks. How can I access property inside the component. Something like this:

export default Ember.Component.extend({
  cMsg: Ember.computed('msg', function() {
            return `${this.get('msg')} , ${this.get('msg')}`;
        }),

  selectedDomain: { msgPrefix: 'cMsg???' },  
});

Here is the twiddle: http://ift.tt/2i3lFJG