ember-bootstrap/116

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
  init() {
    this.set('useIconsIsDefault', 
      !this.attrs.hasOwnProperty('useIcons')
    );
    this._super(...arguments);
  },
  
  useIcons: true
});

controllers.application.js

import Ember from 'ember';

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

templates.application.hbs

<h1>no block, no override</h1>
{{my-component}}

<h1>no block, but override</h1>
{{my-component useIcons=false}}

<h1>block without override</h1>
{{#my-component}}{{/my-component}}

<h1>block with override</h1>
{{#my-component useIcons=true}}{{/my-component}}

templates.components.my-component.hbs

{{#if hasBlock}}
  {{#if useIconsIsDefault}}
    <p>Do not show icons.</p>
  {{else}}
    <p>{{useIcons}}</p>
  {{/if}}
{{else}}
  <p>{{useIcons}}</p>
{{/if}}

twiddle.json

{
  "version": "0.10.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.6.0",
    "ember-data": "2.6.1",
    "ember-template-compiler": "2.6.0"
  },
  "addons": {}
}