How to get and set models from a nested Json Structure using backbone

Question

I am a newbie to Backbone and need help to get and set the models from a nested Json Structure using Backbone

I have a simple model and collection below

Model:

var PmaslDataModel = Backbone.Model.extend({ });

Collection:

app.PmaslDataCollection = Backbone.Collection.extend({
          url APPLICATION_URL+'aslview/getformatedDataRows',
          model         : PmaslDataModel 
    });

Initialize the collection

var pmaslDataCollection =   new app.PmaslDataCollection();

Fetching the above collection returns the data in the Json Format below

{
"id"    : "1",
"rowid" : "1",
"group" : "10__",
"datarows": [
             {
               "id": "sspvk_code",
               "default_display": "1",
               "order": "1",

            },
            {
               "id": "sspvk_code2",
               "default_display": "0",
               "order": "0",
           },
           {
               "id": "sspvk_code3",
               "default_display": "1",
               "order": "0",
           }
         ]
},
{
   "id"    : "2",
   "rowid" : "2",
   "group" : "11__",
   "datarows": [
                {
                  "id": "sspvk_code",
                  "default_display": "1",
                  "order": "1",

                },
                {
                   "id": "sspvk_code2",
                   "default_display": "0",
                   "order": "0",
                },
                {
                   "id": "sspvk_code3",
                   "default_display": "1",
                   "order": "0",
                }
            ]
}

I have to use the above structure to populate the values in a table where we have the row ids and the column values in the row appears in the datarows attributes

I have 2 Questions

How can I set the "default_display" value to 0 for all the datarows with id=sspvk_code ?
If I have a particular row id how can I fetch the datarows for that row,pass it to a underscore template and populate the template (that is ,in the template I need to access it with model.get('attributename value')

Marek Ka. Marek Ka. · Accepted Answer · 2014-07-22T13:55:52

1) To initially set default_display to 0 to all datarows with id "sspvk_code" (is that what you want?) you can use parse method like this I would say:

app.PmaslDataCollection = Backbone.Collection.extend({
  url   : APPLICATION_URL+'aslview/getformatedDataRows',
  model : PmaslDataModel,

  parse : function (response) {
    // ititerate through entire collection
    _.each(response, function (row) {
      // find datarow with sspvk_code id and set default_display to 0
      _.each(row.datarows, function (datarow) {
        if (datarow.id === "sspvk_code") {
          datarow.default_display = 0;
        }
      })
    })

    return response;
  }
});

2) What you mean by "fetch datarows"? Your JSON looks like you already have datarows in collection.

How to get and set models from a nested Json Structure using backbone

2 Answers