Nested CPs

controllers.application.js

import Ember from 'ember';

const statKeys = ['a', 'b', 'c'];

// A computed property macro that generates a "double property X" CP
function makeDoubleComputed(key) {
  return Ember.computed(key, function() {
    const thing = Ember.get(this, `stats.${key}`);
    console.log(this);
    return 2 * thing;
  })
}

// Some basic Ember class
const Thing = Ember.Object.extend({
  stats: null
});

// Reopen the constructor and add the `doubleStats` key, with the value set of an object of computed properties
Thing.reopen({
  doubleStats: statKeys.reduce((acc, statKey) => {
    Ember.set(acc, statKey, makeDoubleComputed(statKey));
    return acc;
  }, {})
});

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  init() {
    this._super(...arguments);
    this.set('thing', Thing.create({stats: { a: 1, b: 2, c: 3}}));
  }
});

templates.application.hbs

<h1>Computed Property Macro Puzzle</h1>

<p>
  Is it possible to dynamically create a set of nested computed properties on the constructor of an Ember.Object?
  <br />
  <br />
  If so, what am I missing?
</p>

<h2>For example:</h2>

<h4>Should be 2: {{thing.stats.b}}</h4>

<h4>Should be 4: {{thing.doubleStats.b}}</h4>

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"
  }
}