How to get Fields from store in ExtJS5

Question

I created a normal window in ExtJS5 which has one grid and one button. I want to get store field items from grid store and want to do another functionality.

When i get store.fields, it shows null. But if i get in ExtJS3, then it works proper.

In below image, I am getting store fields or fields items in ExtJS3.

Here is my code (ExtJS5)

Ext.onReady(function () {
                var States = Ext.create('Ext.data.Store',
                {
                    fields: ['value'],
                    data:
                    [
                        { "value": "HR" },
                        { "value": "DL" },
                        { "value": "RJ" }
                    ]
                });

                var window = new Ext.Window({
                    id: 'grdWindow',
                    width: 400,
                    title: 'Grid Samples',
                    items: [
                        {
                            xtype: 'panel',
                            layout: 'fit',
                            renderTo: Ext.getBody(),
                            items: [
                                {
                                    xtype: 'button',
                                    text: 'Submit',
                                    handler: function () {
                                        var storeFields = Ext.getCmp('grdSample').getStore().fields;
                                        //storeFields get null;
                                    }
                                },
                                {
                                    xtype: 'grid',
                                    id: 'grdSample',
                                    store: States,
                                    columns: [
                                        {
                                            header: 'Name',
                                            dataIndex: 'value'
                                        }
                                    ]
                                }
                            ]
                        }]
                }).show();
            });

Answer 1

grid.getStore().getModel().getFields() should do what you want.