Saving Ember-Data records - ember.js

Question

Questions:
This line of code _activeAuthor.get('books').pushObject(book).save(); is processed without error in Chrome but the book is not added to the books property of the _activeAuthor instance of Ember-Data. I don't understand why?
The below code add the created Book to the Book property of the Chapter instance (see comment). It is a one-to-many relationship (see de Models). Ember-Data seems to automatically populate the related record on the Book instance. Is this a normal behaviour of Ember-Data? Should I let Ember-Data populate the related side of a relationship one-to-many or should I specify both sides and persist both instances?
I suspect that one of the issue of the below code is that the I do not handle promises properly. This code: this.modelFor('user').get('latestChapter'); seems to return a promise. How should I handle promisses with get()?
Code:
createChapter: function() {
//Getting the Author of the latestChapter or getting the first Author in the array
var _activeAuthor = null;
var authors = this.modelFor('user').get('authors').toArray();
var latestChapter = this.modelFor('user').get('latestChapter');
var latestAuthor = latestChapter.get('author');
if (latestChapter.content) {
_activeAuthor = latestAuthor;
} else {
_activeAuthor= authors[0];
}
var book = this.store.createRecord('book', {
title: 'click here to name your book',
author: _activeAuthor,
});
var chapter = this.store.createRecord('chapter', {
title: 'Click here to name your chapter',
book: book, // Add the created Book to the Book property of the Chapter instance
});
_activeAuthor.get('books').pushObject(book).save();
chapter.save();
book.save();
this.modelFor('user').set('latestChapter', chapter).save() //Identifying the latest created chapter at the lastestChapter;
console.log('New chapter created: ' + chapter.get('id'));
},
Models:
App.Author = DS.Model.extend({
type: DS.attr('string'),
authorTitle: DS.attr('string'),
userTitle: DS.attr('string'),
description: DS.attr('string'),
user: DS.belongsTo('user', {inverse: 'authors', async: true}),
books: DS.hasMany('book', { inverse: 'author', async: true}),
});
App.Book = DS.Model.extend({
title: DS.attr('string'),
icon: DS.attr('string'),
description: DS.attr('string'),
frequency: DS.attr('string'),
chapters: DS.hasMany('chapter', { inverse: 'book', async: true}),
author: DS.belongsTo('author', { inverse: 'books', async: true}),
});
App.Chapter = DS.Model.extend({
title: DS.attr('string'),
description: DS.attr('string'),
frequency: DS.attr('string'),
unit: DS.attr('string'),
aggregationMode: DS.attr('string'),
dashboard: DS.attr('boolean'),
statData : DS.attr('array'),
book: DS.belongsTo('book', { inverse: 'chapters', async: true}),
});
Thanks!

Answer 1

1.
author.get('books') will return a promise, so probably what you want to do is
author.get('books').then(function(books) {
books.pushObject(book)
});
author.save();
If this is not an issue, could you give a jsfiddle with the whole app code? Then, it'll be easier to help! :)
2.
Every time you get a model's property that is async and is not isLoaded (not synced with server), ember will ask the server and yes, will populate the records in your store which is a desired behaviour :)
3.
If you have an async model property, then you always get a promise, so you should handle it in for example this way:
chapter.get('book').then(function(book) {
// here's a book
});
BTW var latestAuthor = latestChapter.get('author'); -> chapter doesn't have author property :)