How to reload Ext.tree.TreePanel on demand?

I want to create Ext.tree.TreePanel component and periodically load content from the external URl. So I've written something like

 new Ext.tree.TreePanel({
        root: {
            nodeType: 'async',
            text: 'asdasd',
            draggable: false,
            id: 'folders-tree-root'
        },
        loader: new Ext.tree.TreeLoader()
});

And now I want to reload this tree, so I write:

tree.loader.dataUrl = 'folders-sample.json';
tree.root.reload();

And nothing happens.

add: The only way I've found is set some invalid value to dataUrl param on TreeLoader creation:

 new Ext.tree.TreePanel({
        root: {
            nodeType: 'async',
            text: 'asdasd',
            draggable: false,
            id: 'folders-tree-root'
        },
        loader: new Ext.tree.TreeLoader(dataUrl: 'something')
});

What you're looking for is the load method for the TreeLoader. So something like this should work given your example.

tree.getLoader().load(tree.root);

Here's my full example that's available on my demo site as well. It's a little contrived and hacked together from one of the ExtJS demo's but it should get you what you need.

Ext.onReady(function() {
    var root = new Ext.tree.AsyncTreeNode({
        text: 'Ext JS',
        id: 'src'
    });
    var reloadTree = function() {
        tree.enable();
        tree.getLoader().dataUrl = 'get-nodes2.php';
        tree.getLoader().load(tree.root);
    };

    var tree = new Ext.tree.TreePanel({
        animate: true,
        autoScroll: true,
        nodeType: 'async',
        loader: new Ext.tree.TreeLoader(),
        containerScroll: true,
        border: false,
        disabled: true,
        id: 'myTree'
    });

    var myPanel = new Ext.Panel({
        items: tree,
        border: false,
        tbar: [{
            text: 'Refresh',
            handler: reloadTree
        }]
    });

    tree.setRootNode(root);
    myPanel.render('tree');
});

Cheers