creating nested structure with backbone-relational - backbone.js

Question

I'm trying to create a three cascading dropdown lists. First one constains projects, second contains tasks for selected project and the last one sites for selected task.
I want to use the Backbone-Relational plugin, but have hard time to create the proper relations. That's my first time with this plugin.
Code so far:
App.Models.ProjectItem = Backbone.RelationalModel.extend({
default: {
id: 0,
name: ''
},
relations: [{
type: Backbone.HasMany,
key: 'tasks',
relatedModel: App.Models.TaskItem,
//includeInJSON: Backbone.Model.prototype.idAttribute,
collectionType: App.Collections.TasksCollection,
reverseRelation: {
key: 'projectId',
//includeInJSON: Backbone.Model.prototype.idAttribute,
type: Backbone.HasOne
}
}]
});
App.Collections.ProjectsCollection = Backbone.Collection.extend({
model: App.Models.ProjectItem
});
App.Models.TaskItem = Backbone.RelationalModel.extend({
default: {
id: 0,
name: ''
},
relations: [{
type: Backbone.HasMany,
key: 'sites',
relatedModel: App.Models.SiteItem,
includeInJSON: Backbone.Model.prototype.idAttribute,
collectionType: App.Collections.SitesCollection,
reverseRelation: {
key: 'taskId',
//includeInJSON: Backbone.Model.prototype.idAttribute,
type: Backbone.HasOne
}
}]
});
App.Collections.TasksCollection = Backbone.Collection.extend({
model: App.Models.TaskItem
});
App.Models.SiteItem = Backbone.RelationalModel.extend({
default: {
id: 0,
name: ''
}
});
App.Collections.SitesCollection = Backbone.Collection.extend({
model: App.Models.SiteItem
});
Creating single project:
var item = new App.Models.ProjectItem({
id: 1,
name: 'project',
tasks: [
{
id: 1,
name: 'task',
sites: [
{
id: 1,
name: 'site'
}
]
}
]
})
This object serialized to json looks like this:
"{"id":1,"name":"task","tasks":[1],"sites":[{"id":1,"name":"site"}],"projectId":null}"
My questions:
1) Why the sites array is not nested in the tasks one?
2) Sites collection is not serialized the same way that tasks one is. Should I create a relations in the site model too?
3) Why the projectId is returned for the root?

Answer 1

After many hours of trials and errors I finally got it. The order matters..
Working code:
App.Models.SiteItem = Backbone.RelationalModel.extend({
default: {
siteId: 0,
name: ''
}
});
App.Collections.SitesCollection = Backbone.Collection.extend({
model: App.Models.SiteItem
});
App.Models.TaskItem = Backbone.RelationalModel.extend({
default: {
taskId: 0,
name: ''
},
relations: [{
type: Backbone.HasMany,
key: 'sites',
relatedModel: App.Models.SiteItem,
//includeInJSON: Backbone.Model.prototype.idAttribute,
collectionType: App.Collections.SitesCollection,
reverseRelation: {
key: 'task',
includeInJSON: 'taskId',
type: Backbone.HasOne
}
}]
});
App.Collections.TasksCollection = Backbone.Collection.extend({
model: App.Models.TaskItem
});
App.Models.ProjectItem = Backbone.RelationalModel.extend({
default: {
projectId: 0,
name: ''
},
relations: [{
type: Backbone.HasMany,
key: 'tasks',
relatedModel: App.Models.TaskItem,
// includeInJSON: 'taskId',
collectionType: App.Collections.TasksCollection,
reverseRelation: {
key: 'project',
includeInJSON: 'projectId',
type: Backbone.HasOne
}
}]
});
App.Collections.ProjectsCollection = Backbone.Collection.extend({
model: App.Models.ProjectItem
});
For sample data:
var item = new App.Models.ProjectItem({
projectId: 2,
name: 'first',
tasks: [
{
taskId: 1,
name: 'task',
sites:[{siteId:1, name: 'site'}]
}
]
});
I got this json string:
"{"projectId":2,"name":"first","tasks":[{"taskId":1,"name":"task","sites":[{"siteId":1,"name":"site","task":1}],"project":2}]}"