title: Get store data items value in sencha ext js
body: <p>I have this data in a JSON file.</p>
  
  <pre><code>{
      data: [
          {
              lari: 1.75
          }
      ]
  }
  </code></pre>
  
  <p>I want get this lari's value e.g.:</p>
  
  <pre><code>var lari = mystore.data.items[0];
  </code></pre>
  
  <p>I'm using this code:</p>
  
  <pre><code>Ext.define('Currency.store.mystore',
      { extend: 'Ext.data.Store', requires: 
         [ 'Currency.model.MyModel', 'Ext.data.proxy.Ajax', 'Ext.data.reader.Json' ],
         constructor: function(cfg) {
            var me = this;
             cfg = cfg || {};
             me.callParent([Ext.apply({
                 model: 'Currency.model.MyModel', storeId: 'mystore',
                 proxy: { type: 'ajax', url: 'data.json',
                   reader: { type: 'json', root: 'data' 
  ...
  
  Ext.encode(Ext.pluck(mystore.data.items[0], 'data'));
  </code></pre>
  
  <p>but I have an error:</p>
  
  <blockquote>
    <p>Uncaught ReferenceError: mystore is not defined<br>
    userclassname: 'mystore',</p>
  </blockquote>
  
  <p>Please help me. How to write this code?</p>