For questions regarding Aura.Action. An Aura.Action is a reference to an action in the framework.

Although Aura.Action works for passing an action handler to a child component, we recommend registering an event in the child component and firing the event in the child’s controller instead

  • Don’t use cmp.set() in JavaScript code to reset an attribute of type="Aura.Action" after it’s previously been set. Doing so generates an error.
  • Don’t use $A.enqueueAction() in the child component to enqueue the action passed to the Aura.Action attribute.

For more on the component, refer to the Developer Documentation:

Using the Aura.Action Attribute Type