title: How can nodes in a material tree be hidden based on a condition?
body: <p>I have the problem that I'd like the <code>data.source</code> of my material tree to <em>include more nodes</em> than the actual displayed tree. The reason for this is because I'd like to use the <code>getDescendants</code> method of the tree control, so I need those nodes to be present on the dataSource, just not displayed in the DOM to the user. How can this be achieved? I am using FlatTree.</p>