Computed in Beginning

components.my-profile.js

import Ember from 'ember';

export default Ember.Component.extend({
  optionArr: Ember.computed('optionIndex', function() {
		var arr = [false, false, false];
		arr[this.optionIndex] = true;
		return arr;
	}),
  
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

templates.application.hbs

{{my-profile optIndex=2}}

templates.components.my-profile.hbs

Selected Option = {{optIndex}}
<br><br>
{{optionArr.[0]}} - {{optionArr.[1]}} - {{optionArr.[2]}}

twiddle.json

{
  "version": "0.12.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.12.0",
    "ember-template-compiler": "2.12.0",
    "ember-testing": "2.12.0"
  },
  "addons": {
    "ember-data": "2.12.1"
  }
}