Subcomponents and Component References
A "node" in a template's object graph can represent a subcomponent (also called a reusable component) as well as a dynamic or static HTML element. A dynamic element called a component reference represents all occurrences of the subcomponent in the parent component. At runtime, the component reference binds itself to the separate instances. Figure 26 is an example of an object graph for a page with a subcomponent.
A subcomponent can fire actions against its parent component (using performParentAction:), and if the parent's state changes, its state is synchronized accordingly. In other words, its state is updated to reflect changes according to its bindings with the parent.