New Twiddle

controllers.application.js

import Ember from 'ember';
import { inject as service } from '@ember/service';
import { filterBy } from '@ember/object/computed';

export default Ember.Controller.extend({
	store: service(),
  
  appName: 'Ember Twiddle',
  
  programTags: filterBy('model.program.tags', 'id', true)
  
  actions: {
  	deleteTag(tag) {
			tag.unloadRecord();
    }
  }
});

models.program.js

import Model from 'ember-data/model';
import attr from 'ember-data/attr';
import { belongsTo, hasMany } from 'ember-data/relationships';

export default Model.extend({
  title: attr('string'),
  tags: hasMany('tag')
});

models.tag.js

import Model from 'ember-data/model';
import attr from 'ember-data/attr';
import { belongsTo, hasMany } from 'ember-data/relationships';

export default Model.extend({
  name: attr('string'),
  programs: hasMany('program')
});

routes.application.js

import Ember from 'ember';
import { inject as service } from '@ember/service';

export default Ember.Route.extend({
  store: service(),
  
	beforeModel() {
		this.store.pushPayload({
    	data: [
        {
        	type: 'program',
          id: 1,
          attributes: {
          	title: 'Program 1!'
          },
          relationships: {
          	tags: {
            	data: [{type: 'tag', id: 1}, {type: 'tag', id: 3}]
            }
          }
        },
        {
          type: 'tag',
          id: 1,
          attributes: { name: 'foo' }
        },
				{
          type: 'tag',
          id: 2,
          attributes: { name: 'bar' }
        },
				{
          type: 'tag',
          id: 3,
          attributes: { name: 'baz' }
        }
      ]
    })
  },
  
  model() {
		return {
    	program: this.store.peekRecord('program', 1),
      allTags: this.store.peekAll('tag')
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

Program Title: {{model.program.title}}<br>

Program Tags:<br>
<ul>
	{{#each model.program.tags key="id" as | tag |}}
		{{#if tag}}
	    <li>{{tag.name}}</li>
    {{/if}}
	{{/each}}
</ul>

All Tags:
<ul>
	{{#each model.allTags key="id" as | tag |}}
		<li>
    	{{input value=tag.name}}<br>
      Programs: {{tag.programs.length}}<br>
      <button type="button" {{action "deleteTag" tag}}>Delete</button>
		</li>
	{{/each}}
</ul>

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"
  }
}