EmberJS

// Shopmaster/frontend/app/routes/grocery-lists/new.js
  
import Ember from 'ember';

export default Ember.Route.extend({
  setupController: function(controller, model) {
  controller.set('model', model);
},

model: function() {
  return this.store.createRecord('grocery-list');
},

actions: {
  save: function() {
    var model = this.get('controller.model');
    var _this = this;
    var promises = [];

    model.save().then(function(groceryList){
      groceryList.get('items').forEach(function(item) {
        promises.push(item.save());
      });
        return Ember.RSVP.all(promises).then(function () {
          _this.transitionTo('grocery-lists.index');
        }).catch(function () {
          console.log('one of the saves failed');
        });
      });
    }
  }

});