Entity sample

components.entity-figure.js

import Ember from 'ember';

export default Ember.Component.extend({

});

components.entity-object.js

import Ember from 'ember';

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

controllers.application.js

import Ember from 'ember';

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

templates.application.hbs

<h2>Has image</h2>

{{#entity-figure}}
  {{#if true}}
    <img src="https://placekitten.com/100/100" alt="kitty">
  {{/if}}
{{/entity-figure}}

<h2>No image</h2>

{{entity-figure}}

{{#entity-figure}}
  {{#if false}}
    <img src="https://placekitten.com/100/100" alt="kitty">
  {{/if}}
{{/entity-figure}}

templates.components.entity-figure.hbs

{{#if hasBlock}}
  {{yield}}
{{else}}
  <img src="http://www.myiconfinder.com/uploads/iconsets/256-256-8f47e792bc78fa4b0a2afd1b439129c9-ghost.png" alt="ghost" height=100 width=100> 
{{/if}}

templates.components.entity-object.hbs

{{#if hasBlock}}
	{{#entity-figure}}
    {{yield}}
	{{/enity-figure}}
{{/if}}

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}