Irritable Iterables

controllers.application.js

import Ember from 'ember';

function makeIterable(someObject) {
  someObject[Symbol.iterator] = function() {
    let nextIndex = 0;

    return {
      next: function() {
        if (nextIndex < someObject.order.length) {
          return { value: someObject[someObject.order[nextIndex++]], done: false };
        } else {
          return { done: true };
        }
      }
    };
  }

  return someObject;
}

export default Ember.Controller.extend({
  someIterableObject: Ember.computed(function() {
    return makeIterable({
      b: 'world',
      a: 'hello',
      order: ['b', 'a', 'b']
    });
  })
});

templates.application.hbs

{{#each someIterableObject as |item|}}
	{{item}}
{{else}}
  Didn't iterate.
{{/each}}

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"
  }
}