MapBy

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  field: Ember.computed(function() {
    return Ember.Object.create({
      fieldCategoryFields: [
        Ember.Object.create({
          fieldCategory: Ember.Object.create({
	          name: 'Category 1'
          })
        }),
        Ember.Object.create({
        	fieldCategory: Ember.Object.create({
          	name: 'Category 2'
        	})
        }),
        Ember.Object.create({
        	fieldCategory: Ember.Object.create({
         	  name: 'Category 3'
          })
        })
       ]
    })
  }),
        
  categoryNames: Ember.computed.mapBy('field.fieldCategoryFields', 'fieldCategory.name')
});

templates.application.hbs

<h1>MapBy</h1>
<br>
<br>
{{#each categoryNames as |name|}}
{{name}}
{{/each}}
<br>
<br>

twiddle.json

{
  "version": "0.10.6",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.9.0",
    "ember-data": "2.9.0",
    "ember-template-compiler": "2.9.0",
    "ember-testing": "2.9.0"
  },
  "addons": {}
}