The build function meets the definition of the Builder API and is used to define the declarative UI description of components. Components must comply with the preceding Builder API constraints. Custom or preset components are combined in declarative mode in the build method. The build method is called when a component is created or updated.
> ![icon-note.gif](public_sys-resources/icon-note.gif) **NOTE**:> The build method supports only composite components and uses the rendering control syntax.