Computed Property Caching

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  defaultItem: 'foo',
  
  item: Ember.computed(function() {
    return this.get('defaultItem')
  }),
  
  actions: {
    setItem(val) {
      this.set('item', val);
    },
    setDefaultItem(val) {
      this.set('defaultItem', val);
    },
  }
});

templates.application.hbs

<p>Default Value: {{defaultItem}}</p>
<p>Current Value: {{item}}</p>

<button {{action "setItem" "bar"}}>Set item to bar</button>
<button {{action "setItem" "wat"}}>Set item to wat</button>
<button {{action "setDefaultItem" "sloth"}}>Set default item to sloth</button>

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"
  }
}