Backbone js model response array to Backbone collection

0
votes

If I have a model with some parameters that are collections, as an example:

var Mdl = Backbone.Model.extend({

  defaults:{
    test: new Backbone.Collection()
  }
});

Now lets say I do a fetch on this model, and in my server side response I have a property called "test" which is an array. I would like to add the array to my collection or reset it with this array so that it remains a backbone collection, however this is not done by default if I run a reset on my model, as expected, it will overwrite the "test" property with the array in the response.

What is the best way to get it to treat the response property "test" as a backbone collection instead of array? I basically want to check if the property is an array, then check if the property is already defined on the model as a collection, if so then reset this collection with the array rather then overwriting it.

I could do this by creating my own Backbone Sync, but I am not sure if this is the best way togo about it, what do you guys think?

Thanks.

2
javascriptbackbone.js
you don't need the override for Sync. Backbone provides parse method which takes the response documentcloud.github.com/backbone/#Model-parse you will have to write code to do what you want now - Deeptechtons
do you do this actually ? new Backbone.Collection() i rather create a instance of the collection like below. var tstCol = Backbone.Collection.extend({}); ... defaults:{test:new tstCol()}... - Deeptechtons

2 Answers

0
votes

First thing you are gonna have weird problems if you define Objects in the Model.defaults check this answer.

If you really want to do this try to do it in a delayed function:

// code no tested
var Mdl = Backbone.Model.extend({
  defaults:{
    test: function() { return new Backbone.Collection() }
  }
});

Still I think is not a good idea, I really prefer to have basic values in the Model.attributes I think is what Backbone is expecting.

What I do in this cases is making the server JSON response to have a key called test_data and parse it by hand in the Model.initialize:

// code no tested
var Model = Backbone.Model.extend({
  initialize: function(){
    this.test = new Backbone.Collection( this.get( "test_data" ) );
  }
});

Check this SO question

See that Model.get("test_data") is raw data and that the real Object is Model.test, this last is not included in Model.attributes.

0
votes

I use Backbone Relational for this kind of problem.

You would write code like this to define the relations.

Mdl = Backbone.RelationalModel.extend({
    relations: [{
            type: Backbone.HasMany,
            key: 'test',
            relatedModel: 'TestModel',
            collectionType: 'TestCollection',
            reverseRelation: {
                key: 'mdl'
            }
        }]
});

TestModel = Backbone.RelationalModel.extend({});

TestCollection = Backbone.Collection.extend({
    model: TestModel
});

It will then turn your test attribute into a Backbone Collection.