Ext.data.NodeInterface class is a set of methods that are applied to the model to decorate it with a node API. This means that when we use a model with a tree, the model will have all the tree-related methods. This class also creates extra fields on the model to help maintain the tree state and the UI.
Some of the field's configurations are as follows:
text: This property configures the text to show on the node label.
root: This property is true if this is the root node.
leaf: If this property is set to true, it indicates that this child can have no children. The expand icon/arrow will not be rendered for this node.
expanded: This property is true if the node is expanded.
iconCls: This property configures the CSS class to apply for this ...