Uncaught typeError: Cannot read property 'isModel' of undefined

HI im getting this error after executing my code. It says "Uncaught typeError: Cannot read property 'isModel' of undefined".Im trying to display a list using my defined model named "model.login" and a store with dummy data.

Ext.Loader.setConfig({
enabled: true,
paths:{
    'model' : 'app/model',
    'store' : 'app/store'
}

});
Ext.application({
    name: 'GS',
    launch: function(){
        var myStore = null;
        Ext.require('model.login', function(){
            var login = Ext.create('model.login');
            myStore = new Ext.data.Store({
                model: login,
                data:[
                      {id:'09803' , issued_at: 'thisurl', instance_url:'https', signature:'token', access_token:'ser'}
                      ]
            });
        });
        this.viewport = new Ext.Panel({
            fullscreen: true,
            items:[
                   {
                       xtype: 'list',
                       itemTpl: '{id}',
                       store: myStore
                   }
                   ]
        });
    }

});

Your call to create the viewport is happening before model.login is loaded and your store is created. Move the code to create the viewport into the callback for your Ext.require.

Also, when passing a model into the store, you pass the model constructor, not an instance of it.

Ext.application({
  name: 'GS',
  launch: function(){
    this.viewport = 
    var me = this;
    Ext.require('model.login', function(){                
      myStore = new Ext.data.Store({;

      me.viewport = new Ext.Panel({
        fullscreen: true,
        // You can pass a single item into item
        items:{
          xtype: 'list',
          itemTpl: '{id}',
          store: myStore
        }
      });
    });
  }
});

Note that there's a better way to do this, you can tell the application what models to load and inline some of your calls to make it easier to read

Ext.application({
  name: 'GS',
  models: 'login', // looks in GS.model.login
  launch: function(){
    me.viewport = new Ext.Panel({
      fullscreen: true,
      // You can pass a single item into item
      items:{
        xtype: 'list',
        itemTpl: '{id}',
        store: {
          model: 'model.login', // or GS.model.login without quotes
          data:[              
            {id:'09803' , issued_at: 'thisurl', instance_url:'https', signature:'token', access_token:'ser'}]
          }
       }
    });
  }
});