This topic lists what is inherited when you extend a definition, such as a component.
When a component contains another component, we refer in the documentation to parent and child components in the containment hierarchy. When a component extends another component, we refer to sub and super components in the inheritance hierarchy.
A sub component that extends a super component inherits the attributes of the super component. Use <aura:set> in the markup of a sub component to set the value of an attribute inherited from a super component.
A sub component that extends a super component can handle events fired by the super component. The sub component automatically inherits the event handlers from the super component.
The super and sub component can handle the same event in different ways by adding an <aura:handler> tag to the sub component. The framework doesn't guarantee the order of event handling.
A sub component's helper inherits the methods from the helper of its super component. A sub component can override a super component's helper method by defining a method with the same name as an inherited method.
A sub component that extends a super component can call actions in the super component's client-side controller. For example, if the super component has an action called doSomething, the sub component can directly call the action using the {!c.doSomething} syntax.