ED meta

models.foo\.js

import Model from 'ember-data/model';
import attr from 'ember-data/attr';

export default class FooModel extends Model {
  @attr name;
  @attr meta;
}

routes.application\.js

import Route from '@ember/routing/route';
import { inject } from '@ember/service';

export default class extends Route {
  @inject store;
  
  model() {
    const restPayload = {
      foo: {
        id: 1,
        name: 'Foo 1',
        meta: {
          foo: 'bar' 
        }
      },
    };
    
    const Foo = this.store.modelFor('foo');

    const fooSerializer = this.store.serializerFor('foo');
  
    const jsonApiPayload = fooSerializer.normalizeResponse(this.store, Foo, restPayload, null, 'findRecord');

    this.store.push(jsonApiPayload);
    
    const foo1 = this.store.peekRecord('foo', 1);
    
    console.log('Got meta?', foo1.meta);
  }
}

serializers.foo\.js

import RESTSerializer from 'ember-data/serializers/rest';

export default class FooSerializer extends RESTSerializer { }

templates.application\.hbs

See console

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0",
    "ember-data": "3.18.0"
  }
}