Failing Computed Binding

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  foo: false,
  
  didReceiveAttrs() {
    this._super(...arguments)
    Ember.$.ajax({
      url: `//code.highcharts.com/mapdata/countries/us/us-ca-all.js`,
      dataType: 'script'
    }).then(() => {
      _this.set('foo', true)
    })
  },
  something: Ember.computed('foo', function() {
    if (this.get('foo')) {
      return "set";
    } else {
      return "unset";
    }
  })
});

routes.index.js

import Ember from 'ember';

export default Ember.Route.extend({
});

templates.application.hbs

hello
{{outlet}}
{{my-component}}

templates.components.my-component.hbs

{{yield}}
hello
{{something}}

twiddle.json

{
  "version": "0.7.2",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.4.4/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.4.3/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.4.4/ember-template-compiler.js"
  }
}