Ember Data

timeline-item.js

import DS from 'ember-data';

export default DS.Model.extend({
  timeline: DS.belongsTo("timeline"),
  type: DS.attr("string")
});

timeline.js

import DS from 'ember-data';
import Ember from "ember";

var inflector = Ember.Inflector.inflector;
inflector.uncountable('timeline');

export default DS.Model.extend({
  kitten: DS.belongsTo("kitten"),
  items: DS.hasMany("timelineItem", {polymorphic: true})
});

timeline.json

timeline: [
    {
      id: "meowzah",
      kitten: "meowzah",
      items: [
        {
          id: "whatup",
          type: "Email",
          title: "Sup dude",
          content: "meow mix meow mix please deliver",
          contentSummary: "meow..."
        },
        {
          id: "blah",
          type: "Note",
          content: "meow mix meow mix please deliver",
          contentSummary: "meow..."
        }
      ]
    }
  ]