Sample for DS.Model without attr

models.author.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'),
  nameWithoutAttr: attr()
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  beforeModel() {
    this.store.push({
			"data": [{
				"type": "author",
				"id": "1",
				"attributes": {
					"name": "A",
					"nameWithoutAttr": "Abhilash"
				}
			}, {
				"type": "author",
				"id": "2",
				"attributes": {
					"name": 1,
					"nameWithoutAttr": true
				}
			}]
		});
	},
	model() {
		return this.store.peekAll('author');
  }
});

templates.application.hbs

{{#each model as |author|}}
  {{author.name}}
  {{author.nameWithoutAttr}}
  <br />
{{/each}}

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": "2.12.2"
  }
}