App.FlashMessage = Ember.Object.extend({
  type: 'notice',
  dismissable: true,
  message: null,

  isNotice: function(){
    return this.get('type') == 'notice';
  }.property('type'),

  isWarning: function(){
    return this.get('type') == 'warning';
  }.property('type'),

  isAlert: function(){
    return this.get('type') == 'alert';
  }.property('type'),

  isInfo: function(){
    return this.get('type') == 'info';
  }.property('type')
});

App.FlashMessage = Ember.Object.extend({
  type:        'notice',
  message:     null,
  dismissable: true,
  isInfo:      Ember.computed.equal('type', 'info'),
  isAlert:     Ember.computed.equal('type', 'alert'),
  isNotice:    Ember.computed.equal('type', 'notice'),
  isWarning:   Ember.computed.equal('type', 'warning')
});

Use computed properties instead of manually checking equality