controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  queryParams: ['petName'],
  petName: null,
  
  filteredOwners: Ember.computed('petName', '[email protected].[]', function() {
    let petName = this.get('petName');

    return DS.PromiseArray.create({
      promise: Ember.RSVP.filter(this.get('model').toArray(), owner => {
        return owner.get('pets').then( pets => {
          return pets.isAny('name', petName);
        });
      })
    });
  })
});