The render event is fired after all methods in a custom renderer are invoked. For more details on the sequence in the rendering or rerendering lifecycles, see Create a Custom Renderer.
Handling the aura:valueRender event is similar to handling the init hook. Add a handler to your component's markup.
In this example, the onRender action in your client-side controller handles initial rendering and rerendering of the component. You can choose any name for the action attribute.