http://www.sencha.com/forum/showthread.php?109340-Uncaught-TypeError-Cannot-call-method-indexOf-of-undefined&p=511383#post511383

Sencha Touch - Error

Ext.regModel('ListItem', {
    fields: [{id: 'string', name: 'text'}]
});

Ext.setup({
	icon: 'icon.png',
	tabletStartupScreen: 'tablet_startup.png',
	phoneStartupScreen: 'phone_startup.png',
	glossOnIcon: false,
	onReady: function(){
		var data = "";
		Ext.util.JSONP.request({
			url: 'https://graph.facebook.com/me/friends',
			params: {
				access_token: "///TOKEN GOES HERE\\\"
			},
			callbackKey: 'callback',
			callback: function(data) {
				data = data.data;
			}
		});
		var store = new Ext.data.TreeStore({
			model: 'ListItem',
			proxy: {
				type: 'ajax',
				reader: {
					type: 'tree',
					root: 'data'
				}
			}
		});
		
		var nestedList = new Ext.NestedList({
			fullscreen: true,
			title: 'Friends',
			displayField: 'text',
			store: store
		});
	}
});