How do you save a many-to-many relationship in Ember and Firebase

Question

Let's say we have many medicines that can be prescribed to many patients. Our model would look like this:

App.Medicine = DS.Model.extend({
  name: DS.attr(),
  patients: DS.hasMany('user', { async: true }), 
});

App.User = DS.Model.extend({
  name: DS.attr(),
  medicines: DS.hasMany('medicine', { async: true })
});

In this scenario, how do we save records to a Firebase store?

Answer 1

App = Ember.Application.create();

App.ApplicationAdapter = DS.FirebaseAdapter.extend({
  firebase: new Firebase('https://YOUR_FIREBASE.firebaseio.com/')
});


App.Router.map(function(){ });

App.Medicine = DS.Model.extend({
  name: DS.attr(),
  patients: DS.hasMany('user', { async: true }), 
});

App.User = DS.Model.extend({
  name: DS.attr(),
  medicines: DS.hasMany('medicine', { async: true })
});

App.IndexRoute = Ember.Route.extend({
  model: function() {
    var medicines = this.store.find('medicine');
    var users = this.store.find('user');
    return {
      medicines: medicines,
      users: users
    };
  },
  actions: {
    savePost: function(){
      var store = this.store;
      var medicine1 = store.createRecord('medicine', {name: 'aspirin'});
      var patient1 = store.createRecord('user', {name: 'Jane'});
      var patient2 = store.createRecord('user', {name: 'Peter'});
      medicine1.save()
      .then(function(){
        return Ember.RSVP.Promise.all([
          patient1.save(),
          patient2.save()
        ])
       .then(function(){
          var promises = [];
          var patientsOfMedicine1 = medicine1.get('patients');
          var medicinesOfPatient1 = patient1.get('medicines');
          var medicinesOfPatient2 = patient2.get('medicines');
          promises.push(patientsOfMedicine1, medicinesOfPatient1, medicinesOfPatient2);
          return Ember.RSVP.Promise.all(promises);
        })
        .then(function(arrayOfAttachedArrays){
          var promises = [];
          var patientsOfMedicine1 = arrayOfAttachedArrays[0];
          var medicinesOfPatient1 = arrayOfAttachedArrays[1];
          var medicinesOfPatient2 = arrayOfAttachedArrays[2];
          patientsOfMedicine1.addObjects(patient1, patient2);
          medicinesOfPatient1.addObject(medicine1);
          medicinesOfPatient2.addObject(medicine1);
          promises.addObjects(medicine1.save(),patient1.save(),patient2.save());
          return Ember.RSVP.Promise.all(promises);
        });

      });
    }
  }
});

Notes:

• Thanks to David Govea for showing me how this works.
• If there's a better way to do this, please post below.