We describe here a way to work with Embedded Documents and ExtJS Models, especially on the Parsing (GET) part. Embedded documents are a powerful feature of MongoDB, my favorite. A nice alternative to OneToMany SQL Join.
For example, based on a JSON data from a GET query, if we have:
{
"success": true,
"user": [{
"id": 1,
"name": "Philip J. Fry",
"last_post": {
"title": "Post 1", posted:"2015-03-03T12:45:14Z"
}
}]
}
In ExtJS, the models are:
Ext.define('MyApp.model.User', {
extend: 'Ext.data.Model',
fields:[
{ name: 'id', type:'int' }
,{ name: 'name', type:'string' }
,{ name: 'last_post', reference:'Post' }
]
}); // eo MyApp.model.User
and
Ext.define('MyApp.model.Post', {
extend: 'Ext.data.Model',
fields:[
{ name: 'title', type:'string' }
,{ name: 'posted', type:'date' }
]
}); // eo MyApp.model.Post
At this point, even if we could access last_post fields (last_post.title), “date” field is not parsed and so, not transformed into a “Date” object. There are couple of solutions, but my favorite and most efficient is the following: use “convert” function for the “last_post” field.
So, User model becomes:
Ext.define('MyApp.model.User', {
extend: 'Ext.data.Model',
fields:[
{ name: 'id', type:'int' }
,{ name: 'name', type:'string' }
,{ name: 'last_post',
// Here is the trick... =>
convert: function(value) {
return Ext.create("MyApp.model.Post", value).data;
}
}
]
}); // eo MyApp.model.User
By this way, “transformation” is hold by the “convert” function and works efficiently.
References
Alex'Blog 