ExtJs 4.1 - Uncaught Error - Cannot read property "items" of undefined.

[bomslang]

Folks,

I am trying to bring a Json and bind it with the gridpanel in ExtJS 4.1.
I've checked that it's a valid Json returned. But it's not getting bind with gridpanel.

Also, it is showing me one error on console.
error.jpg

Here's my code :-
app.js:-

var record = Ext.data.Record.create([
               {name: 'id'},
               {
                  name: 'name',
                  type: 'string'
             }, {
                name: 'title',
                type: 'string'
             }, {
                name: 'content',
                 type: 'string'
             }
    ]);
        
var reader = new Ext.data.reader.Json({
       root: 'data',
        totalProperty: 'total',
        successProperty: 'success'
}, record);
        
 var writer = new Ext.data.writer.Json({
        encode: true,
       writeAllFields: true
 });
        
var store = new Ext.data.JsonStore({
      proxy: proxy,
     reader: reader,
     writer: writer,
    fields: ['id','content','name','title'],
     autoSave: false
  });




      ....
      ...
items: [
        {
           xtype: 'gridpanel',
           columns: [
                  { text: 'Name',  dataIndex: 'name' },
                  { text: 'Title', dataIndex: 'title' },
                  { text: 'Content', dataIndex: 'content', flex: 1 }
             ],
             store: store
         }       
 ]

Here's my json returned :-

{
    "data": [
        {
            "name": "Person1",
            "id": 1,
            "content": "Hello World",
            "title": "First App"
        },
        {
            "name": "Person2",
            "id": 2,
            "content": "Great ExtJS Application",
            "title": "ExtJS"
        },
        {
            "name": "Person3",
            "id": 3,
            "content": "Best HTML5 framework",
            "title": "Sencha Touch"
        }
    ],
    "total": 3,
    "success": true
}

[bomslang]

I guess, this example runs according to ExtJS 3.0 documentation.

I got it working by checking appropriate syntax'es for similar components in ExtJS 4.1.

Thanks