Serializing Relationships

adapters.application.js

import Adapter from 'ember-data/adapter';

export default Adapter.extend({
  createRecord(_, __, snapshot) {
    return this.serialize(snapshot, { includeId: true });
  },

  updateRecord(_, __, snapshot) {
    return this.serialize(snapshot, { includeId: true });
  }
});

adapters.message.js

import ApplicationAdapter from './application';

let nextID = 1;

export default ApplicationAdapter.extend({
  generateIdForRecord(_, __, inputProperties) {
    return nextID++;;
  }
});

controllers.application.js

import Ember from 'ember';
import { computed } from '@ember/object';
import { reads } from '@ember/object/computed';

export default Ember.Controller.extend({
  client: reads('model.client'),
  message: reads('model.message'),
  
  serializedClient: computed('client', {
    get() {
      let json = this.client.serialize({ includeId: true });
      return JSON.stringify(json, null, 2);
    }
  }),
  
  serializedMessage: computed('message', {
    get() {
      let json = this.message.serialize({ includeId: true });
      return JSON.stringify(json, null, 2);
    }
  })
});

models.client.js

import Model from 'ember-data/model';
import attr from 'ember-data/attr';
import { or, reads } from '@ember/object/computed';

export default Model.extend({
  name: attr('string'),
  isEvicted: attr('boolean', { defaultValue: false }),
  isSelf: attr('boolean', { defaultValue: false }),
  
  address: reads('id'),
  displayName: or('{name,address}')
});

models.message.js

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

export default Model.extend({
  body: attr('string'),
  createdAt: attr('string'),
  type: attr('number'),
  from: belongsTo('client')
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  async model() {
    let client = this.store.createRecord('client', {
      id: '1',
      isSelf: true,
      name: 'Alice'
    });
    await client.save();
    let message = this.store.createRecord('message', {
      type: 1,
      body: 'foobar',
      createdAt: new Date().toISOString(),
      from: client
    });
    await message.save();
    return { client, message };
  }
});

serializers.application.js

import JSONAPISerializer from 'ember-data/serializers/json-api';

export default JSONAPISerializer.extend();

templates.application.hbs

<h2>Client</h2>
<pre><code>{{this.serializedClient}}</code></pre>
<h2>Message</h2>
<pre><code>{{this.serializedMessage}}</code></pre>

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"
  }
}